Compounding Rollover Time

[KingLink32]

Add an option to allow rollover time to compound.

If I set a limit of 5 min per hour and don't use any time for 3 hours I would like the option to use all banked rollover time (20 min total at the 4th hour) currently it will only allow 10 min as 5 min from just the previous hour plus 5 min from the current hour.

Additionally allow a time period for resenting banked time. the default could be if I set it for 0900-1700 then it could reset at the start time each day. but an option to say, I want to store banked time across a week for example.