Remove all references to xvideosink, fix examples (#140845).

Remove all references to xvideosink, fix examples (#140845).

Original commit message from CVS:
* configure.ac:
* examples/capsfilter/capsfilter1.c: (main):
* examples/seeking/spider_seek.c: (make_spider_pipeline):
* ext/dvdread/Makefile.am:
* ext/dvdread/demo-play:
* ext/dvdread/demo-play.c:
* gconf/gstreamer.schemas.in:
* gst-libs/gst/gconf/gconf.c:
* sys/v4l/TODO:
* testsuite/Makefile.am:
* testsuite/embed/Makefile.am:
* testsuite/embed/embed.c: (cb_expose), (main):
Remove all references to xvideosink, fix examples (#140845).
* gst/playback/gstplaybasebin.c: (group_destroy):
Apparently, disposal does not unlink - so do explicitely.
* ext/alsa/gstalsasink.c: (gst_alsa_sink_check_event):
Add debug.