libgsf 1.9.1

J.H.M. Dassen (Ray):
	* Corrected the location where the documentation gets installed.
	*
James Cape :
	* Clean up the gtk-doc build

Jody :
	* Support DOCTYPE in the simplified xml generator
	* More gtk-doc cleanup

Morten, Dom:
	* Avoid polluting global name space with symbols lacking gsf_ prefix.
	  This only effects implementation utilites shared by the zip in/out
	  code so hopefully the abi breakage will not hurt too many people.

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