v1.1f20211011: Fixed thread shift when RPM changes

Fixed shifting the thread start position when the spindle RPM changes.
Fixed fluctuations in the reported RPM when threading starts

Improved Threading synchronization and support for Lichuan A4 servo driver in step/dir mode

Improved Threading synchronization resulting in smoother startup and faster synchronisation
Added support for Lichuan A4 servo driver in step/dir mode
Some minor changes