Add ntp sync code
Add wrapper to get clock which adds NTP base clock

This let implementor set clock as relative to system start,
which is what normal itunes uses.
Signal sync packet to library user

Before NTP synchronization has been established, current system clock
is assumed as reference time for the audio data.

For some reason 11025 samples offset is needed to get a correct sync.
This would seem to correspond with minimum latency often reported
Bump minor for API breakage