BIG CHANGE in techniques...

Had issues with "-vsync 0" and (only!!) flash plugin and our .mp4

So now use "-vsync 1" *and* attempt to sync (stretch/dupe/drop) *audio*
frames to the video timeline, best we can.

Added "MPEG-TS" format to the list of A/V anti-sync deriving.

Better "ffmpeg-version" detection.

Added some comments about various explorations and failures at top, too.
comments, re-indents, etc (nothing substantitive)