gst/mpegaudioparse/gstmpegaudioparse.*: Save some memory for each frame by only savin...

gst/mpegaudioparse/gstmpegaudioparse.*: Save some memory for each frame by only saving the start timestamp and start ...

Original commit message from CVS:
* gst/mpegaudioparse/gstmpegaudioparse.c: (gst_mp3parse_reset),
(gst_mp3parse_emit_frame), (mp3parse_handle_seek):
* gst/mpegaudioparse/gstmpegaudioparse.h:
Save some memory for each frame by only saving the start timestamp
and start byte position instead of additionally the stop timestamp
and stop byte position. This requires us to use a doubly-linked list
but still saves 8-12 bytes per frame.