[mythtv] Experimental HDTV/MPEG2/DVB patches

[Daniel Thor Kristjansson]

I've updated the patches at http://www.mrl.nyu.edu/~danielk/mythtv

Some of them depend on the hdtv signal check patch I submitted to the
list. I've removed the framesPlayed hack and now actually keep track of
the time elapsed using the change in framerate caused by dropping the B
frames. I've added methods to avformatdecoder to makes this easy:
IncrFramesPlayed and SetFramesPlayed. I've also hacked the scan
detection a little so my PVR-250 recorded stuff gets properly detected
as being interlaced for XvMC playback. The XvMC deinterlacing also
started mysteriously working again.

Please test this if you use MPEG2 video, if there are no complaints
in the next week I'll assume it's working and submit the patches for
CVS.

-- Daniel