Change Log:
v0.11.4
  - correct documentation and compiler warnings flagged by CRAN. Some documentation updates.
v0.11.3
  - import networkLite and define as.networkDynamic.networkLite to support tergm applications
v0.11.2
  - corrected trailing quote in maintainer email flagged by CRAN
v0.11.1
  - corrected coercion to logical error in tests flagged by CRAN
  - resolve if() conditions comparing class() to string warning from R devel using is() from methods
v0.11.0
  - update get.edge.attribute.active, get.edge.value.active, get.network.attribute.active, list.edge.attributes.active, and list.network.attributes.active to be compatible with new network generics
v0.10.1
  - update get.vertex.attribute.active and list.vertex.attributes.active to be compatible with new network generics (thanks to chad-klumb!)
  - combined spellfunctions.c into Rinit.c to avoid CRAN-flagged problems with -fno-common flag in gcc
v0.10
  - update to test failing on cran after network 1.14 release
  - updates to network.edgecount.active, network.dyadcount.active and similar to be compatible
  with S3 generics introduced in network 1.14
  - corrections to some internals for rdevel changes to is.na with multiple args
v0.9
  - vignette updates
  - fixed issue where network.collpase would incorrectly nest dynamic network-level attributes if there was only one of them
  - updated McFarland classroom networks to include TEA edge attributes
  - updated as.data.frame.networkDynamic() to mostly fix dramatic speed cost of filtering features from previous release, doc corrections
  - removed warning generated by as.data.frame.networkDynamic() when network has no edge activity to return
v0.8
  - as.data.frame.networkDynamic() will now remove rows corresponding spells that lie outside of the start End censoring range
  - as.data.frame.networkDynamic() will now internally set 'start' and 'end' param to -Inf and Inf if not specified
  - networkDynamic() converter function now processes edge.changes much more quickly when adding edge activity to an empty network.
  - minor documentation fixes
  - explicit S3 method registration,
  - added edges.age.at, verticies.age.at and dyad.ages.at functions to report the age of edges or vertices at a specific time point
v0.7
  - networkDynamic now uses (and requires) C-api exported by the network package
  - additional spell operations moved to C level
  - the networkDynamic() data conversion function as additional arguments "edge.TEA.names"" and "vertex.TEA.names" and can now load dynamic edge or vertex attributes included as extra columns to edge.spells and vertex.spells.
  - pids will now be removed by as.network.networkDynamic()
  - added read.son function for parsing SoNIA-formatted files with dynamic network data
  - added nd_test_nets dataset, a list networkDynamic objects with unusual configurations and parameters to be used for testing
  - fixed bug in spells.overlap and adding missing tests
  - added when.vertex.attrs.match and when.edge.attrs.match functions for getting times at which TEA attributes of network elements match specified values according to specified operators.
  - added nd_test_nets dataset, a list networkDynamic objects with unusual configurations and parameters to be used for testing 

v0.6.3
 - CRAN-request update to fix compatibility of test with testthat v0.8.1

v0.6.2 - Minor fix
 - CRAN-requested update to fix compatibility of test with R-trunk

v0.6 - Features & bug fixes
 New Features:
  - added get.dyads.active function to facilitate looking up the vertex ids of the heads and tails of active edges of a non-hypergraphic network
  - some refactoring of network.extract and network.collapse and get.vertex.attribute.active for speed improvements
  - reimplemented is.active in C to speed up operations on large networks with lots of time steps
  - added adjust.activity() function to transform the all of the known activity spell values in a networkDynamic object
  - converted add.edges to add.edges.networkDynamic, add.edge to add.edge.networkDynamic and add.vertices to add.vertices.networkDynamic to more correctly use S3 dispatching that was added in network v1.9
  - changed argument order of add.edges.active and add.vertices.active to avoid S3 warnings and implemented pass-through for additional arguments. 
 Fixes:
  - Added 'earlier' and 'latest' rules to additional functions for compatibility only: when testing for activity they evaluate the same as 'any'.
  - fixed bug in get.edge.activity(...,as.SpellList=TRUE) that would unexpectedly censor onset and terminus times to net.obs.period if it existed. 
  - add.vertices.active no longer gives an error if the number of vertices to add is zero. 

v0.5.2 - Features & bug fixes
 New Features:
  - network.extract() function now truncates the observation spells of the net.obs.period attribute (if it is present)
  - the networkDynamic() converter function for lists of networks will now convert attributes of the panel networks into TEA attributes of the dynamic network. But vertex attributes of first net in list no longer copied in as static attributes (static attributes will be copied from base.net)
  - added get.networks() function that returns a list of network objects sampled from a networkDynamic
  - added functions to support defining optional 'persistent ids' attributes for vertices and edges that will remain invariant through network extractions: get.vertex.id, get.vertex.pid, for translating between normal (positional) vertex ids and vertex pids, get.edge.id, get.edge.pid do the same for edges, vertex.pid.check, edge.pid.check to verify pid uniqueness, and initialize.pids provides some options for defining the pids.  Overrides add.edges, add.edge, add vertices from network package to allow passing in new ids when creating new network elements.
  - added reconcile.vertex.activity and reconcile.edge.activity functions with various modes for modifying the activity of one set of elements to be consistent with the other
  - support for bipartite networks with size-zero first partition (bipartite=0)
  - implemented 'earliest' and 'latest' aggregation rules for processing attribute queries that might return multiple values
  - added ability to activate multiple spells per vertex by adding duplicate elements to the v elment of activate.vertices
  - added ability for activate.edges to activate multiple spells per edge by repeating values of e argument
  - modified is.active function to give warning if an eid is specified that corresponds to a deleted edge, meaning that the indicies returned will not correspond to indices of the e parameter and valid.eids should be used
  
 Bugs fixed:
  - fixed bug in spells.overlap() when considering null spell (Inf,Inf) and some point queries.
  - dramatic speed improvements to spell list importing via the networkDynamic() function
  - fixed bug in network.edgecount.active and network.naedgecount.active when network has deleted edges (such as ergm sim output). 
  - fixed bug in activate.edge.attributes that could swap edge values in some cases when using e argument.

v0.4.1 - bug fixes
  - fixed problem in delete spell function that would give errors on some deactivate.vertices calls
  - fixed bug in get.vertex.activity(as.spellList=TRUE) when spell activity had been deleted or removed
  - fixed bug in get.change.times that prevented it from checking changes times of TEAs
v0.4 - new functionality and bug fixes
  - networkDynamic() function supports conversion from various tabular schemas (spell-edgelists, toggles, lists of networks)
  - added ability to attach Temporally Extended Attributes (TEAs) to network elements to store and manipulate changing attributes of vertices, edges and networks.
  - specification of an (optional) net.obs.period attribute to store meta-information about the network's period of observation/simulation
  - added network.collapse() function (and %k% operator) which complements network.extract() for extracting an appropriate static network from a dynamicNetwork object
  - added support for networks with zero vertices (feature added in network)
  - addition of as.network.networkDynamic and as.networkDynamic.network to remove and set networkDynamic class on network objects. 
  - added package dependency on statnet.commons for startup message functionality
  - added package suggests to testthat to support more efficient writing of unit tests. 
  - extensive and updated package vignette / tutorial: browseVignettes(package='networkDynamic')
  - numerous bug fixes and documentation improvements

v0.3 - bug fixes and new functionality
	- network.dynamic.check now optionally reports what is wrong with an element
	- new functions get.vertex.activity and get.edge.activity to return activity matrices of elements
	- new function get.change.times to report timepoints at which network structure changes
	- new convienince function add.edges.active and add.vertices.active which add and activate elements in a single call
	- new delete.edge.activity and delete.vertex.activity functions to remove timing information from elements. 
	- activate.* and deactivate.* methods now modify class of network argument in place. 
	- speed and stability improvements to many functions
	- additional examples in help files
	- dactivate.vertices function now includes option to deactivate incident edges

v0.1-0 - Lots of rebuilding
 - added namespaces
 - moved duration.matrix script from ergm code, added some C code
 - update to package loading
 - renamed network.crossection to network.extract
 - ndConverter functions for translating various forms of relational information into networkDynamic format
 - addition of 'at' and 'length' arguments for most temporal methods
 - rebuilt code with increased argument checking for most spell related methods
 - added test cases for most methods
 - some changes in spec for spell handling
 - bug fixes in spell handling for interval queries
 - bug fix to network.dynamic.check
 - added dynamic network datasets of Newcomb's fraternities, Lin Freeman's Windsurfers and McFarland's classroom networks
 - filename of build now includes version information

v0.1-1 - Internal Bugfix Release, w/Minor New Function
  New Functions:
    - network.dynamic.check: Check dynamic consistency of network elements.
  Bug Fixes:
    - Removed tracer statements.  [Submitted by PNK]
    - is.active could fail if passed no edges to check.  [Submitted by PNK]
    - is.active could fail if passed infinite arguments in some cases.

v0.1 - Initial Internal Release