ext/dv/gstdvdec.c: Fix caps negotiation.

ext/dv/gstdvdec.c: Fix caps negotiation.

Original commit message from CVS:
* ext/dv/gstdvdec.c: (gst_dvdec_loop):
Fix caps negotiation.

* ext/dvdnav/dvdnavsrc.c: (dvdnavsrc_class_init),
(dvdnavsrc_update_buttoninfo), (dvdnavsrc_get),
(dvdnavsrc_get_event_mask), (dvdnav_handle_navigation_event),
(dvdnavsrc_event):
* ext/mpeg2dec/gstmpeg2dec.c:
* gst-libs/gst/navigation/navigation.c:
(gst_navigation_send_key_event), (gst_navigation_send_mouse_event):
* gst-libs/gst/navigation/navigation.h:
* gst/mpegstream/gstmpegdemux.c: (gst_mpeg_demux_handle_src_event):
* sys/ximage/ximagesink.c: (gst_ximagesink_handle_xevents):
* sys/xvimage/xvimagesink.c: (gst_xvimagesink_handle_xevents):
Super-simple first version of mouse and keyboard events. Clicking
on a DVD menu now works, although it may not take you where you
expected.

* gst/sine/gstsinesrc.c: (gst_sinesrc_src_fixate):
* gst/videotestsrc/gstvideotestsrc.c:
(gst_videotestsrc_src_fixate):
These fixate functions were broken - they never actually
fixated :)