[mythtv] VideoSync class

[Peter Bennett]

Hi Mark

Since you removed avsync and renamed avsync2, the synchronization 
classes in vsync.cpp are now not needed. However, the VideoSync Object 
is still being created in mythplayer.cpp and a sync method is being 
reported, but as far as I know it is not actually used for anything 
relevant. Do you agree that vsync.cpp and vsync.h should be removed 
together will all references to the classes defined in vsync.h?

Peter