gst/avi/gstavidemux.*: Yeah, implement proper seeking. Exact seeking and segment...

gst/avi/gstavidemux.*: Yeah, implement proper seeking. Exact seeking and segment seeking.

Original commit message from CVS:
* gst/avi/gstavidemux.c: (gst_avi_demux_reset),
(gst_avi_demux_src_convert), (gst_avi_demux_handle_src_event),
(gst_avi_demux_stream_header), (gst_avi_demux_handle_seek),
(gst_avi_demux_process_next_entry), (gst_avi_demux_stream_data),
(gst_avi_demux_loop):
* gst/avi/gstavidemux.h:
Yeah, implement proper seeking. Exact seeking and segment seeking.
Still need to do some checks for segment_stop.