fix LTC alignment.

fix LTC alignment.

LTC-slave: offset the parsed LTC-frame instead of changing the
frame's timestamp. This fixes an issue with freewheel timeout and
delta-calculation. Align transport-time with output to match
capture alignment: "with existing material".

LTC-generator: follow suit. align clock with master-bus out.
This is a semi-permanent workaround. Once [tracks feeding] the
master-bus is/are delayed to align to output. The generator
needs to use (worst_track_latency not worst_playback_latency)