gst/: Support GstPlay, bug fixes, updates.

gst/: Support GstPlay, bug fixes, updates.

Original commit message from CVS:
* gstinterfaces/.cvsignore:
* gstinterfaces/0.7.defs:
* gstinterfaces/Makefile.am:
* gstinterfaces/common.defs:
* gstinterfaces/common.override:
* gstinterfaces/gstinterfacesmodule.c: (init_gstinterfaces):
* gstplay/.cvsignore:
* gstplay/0.7.c:
* gstplay/0.7.defs:
* gstplay/0.7.h:
* gstplay/0.7.override:
* gstplay/Makefile.am:
* gstplay/__init__.py:
* gstplay/arg-types.py:
* gstplay/common.c:
* gstplay/common.h:
* gstplay/common.override:
* gstplay/gstplaymodule.c: (init_gstplay):
* gstreamer/Makefile.am:
* gstreamer/__init__.py:
* gstreamer/common.override:
Support GstPlay, bug fixes, updates.
* examples/gstplay/player.py:
GstPlay example.
* Makefile.am:
Support GstPlay build.
* configure.ac:
Support GstPlay build, remove AC_SUBST() calls that
PKG_CHECK_MODULES does automagically.