[mythtvnz] Audio Synch

[Brett]

Using 0.23+fixes.
I have fairly consistent 80ms A/V sync offset with GT240 & audio s/pdif
output.

I guessed/assumed this was: normal or possibly down to extra video
processing capability ( & enabled) with feature set C GPU.
I was holding out for A/V sync offsets in database for different
sources.

The old 9400GT card did not display this problem with 0.23 (much older
version).