Byoyomi takeback issues

[ianfab]

When using takebacks in byoyomi the behavior sometimes is surprising and partly buggy.

1. The takeback won't give you back a byoyomi period, so if you for example make a move with 1 second of normal time remaining, then go into byoyomi, and then take it back (e.g., with 10 seconds byoyomi on the clock), you end up with 1 second on the clock within byoyomi , i.e., you lose on time immediately. Either one should get back the byoyomi period, or reset to the byoyomi time.
2. When you take back a move within byoyomi, byoyomi just keeps counting down, which often makes it impossible to play an alternative move in time. I think resetting byoyomi time on takeback would make sense.