Original commit message from CVS:
* common/gtk-doc-plugins.mak:
* docs/plugins/Makefile.am:
* docs/plugins/gst-plugins-base-plugins-sections.txt:
* ext/theora/Makefile.am:
* ext/theora/gsttheoraenc.h:
* ext/theora/theoraenc.c:
* ext/vorbis/vorbisenc.c:
pick up signals and args for vorbis; add some docs for vorbis
