Some tidying up in star and itsdaqFW code
Main fixes:
- Add virtual mask register so we can turn on all masks for the digitial scan.
- Skip writing of read-only registers (and warn in the Emu code).
- Also Emu, skip the Fei4 specific padding in releaseFifo
- Don't write the final parameter in StdParameterLoop as it's not used (and may not be valid).