david curtis (crediton), no switch allowed once it's a running game - Geoff Hall's rules!

Ian Henderson (ianfrontbacon) and @IIan Davidson 🇬🇧 (diamondg) I have fixed the issue with Switch and Undo being overlayed with each other. I have a couple of switchgammon matches today so will have opportunity to test it.

Thanks all for reporting the bugs... and for your patience.