prepare combiner for potential shift to retransmission branch and add improved calibration limits generation. fix constrain

switch threshold firmware between DiRICh versions by config and selection of pinout. Add register 0xFE with DiRICH Version info

New feature: bit 20 of config register
  Select or deselect the calibration of channel 0 of local TDC (e.g. on
combiner in CBM RICH) only with trigger 0xD. This is needed as the
trigger signal is correlated to the on board clock

Included MBS, TDC and a online calib entity for MBS-TDC; TDC and calib not used. Still problems with Placing!