inlined more docs, fixed double id-ref

inlined more docs, fixed double id-ref

Original commit message from CVS:
* docs/gst/gstreamer-docs.sgml:
* docs/gst/gstreamer-sections.txt:
* docs/gst/tmpl/.cvsignore:
* docs/gst/tmpl/gsterror.sgml:
* docs/gst/tmpl/gstfilter.sgml:
* docs/gst/tmpl/gsturihandler.sgml:
* docs/gst/tmpl/gsturitype.sgml:
* docs/gst/tmpl/gstutils.sgml:
* docs/gst/tmpl/gstxml.sgml:
* gst/gsterror.c:
* gst/gsterror.h:
* gst/gstfilter.c:
* gst/gsturi.c:
* gst/gsturitype.c:
* gst/gstutils.c:
* gst/gstxml.c:
inlined more docs, fixed double id-ref