Origintimestamp in announce and sync messages should be reserved and 0
Fixing issue with PLL pin drive logic that caused an undesired jump in
frequency.

This would appear as an oscillation in the PI loop output if the
frequency it was trying to recover was in the affected range.
Updating changelog
Updating xpd.xml (xpd version 1.0.12)
Adding support for new rev of audio slice
Updating dependencies via xpd
'Release: 5.2.1rc0'
Updating readme, 1722.1 is no longer draft
'Release: 5.2.1rc1'
Merge pull request #7 from xcore/master

Master merge