Updated 20090507 with:
 - migrate to VLC_TS_INVALID
 - fix coding style
 - use generic handling of DEMUX_SET_TIME
 - don't add +1 to dts/pts
 - zero point hack while VLC_TS_INVALID = 0
Signed-off-by: David Flynn <davidf@rd.bbc.co.uk>
Signed-off-by: Laurent Aimar <fenrir@videolan.org>