Refactor MainClock → ClockSettings

Taking some time before choosing the next big thing to work on to clean up and refactor bits of code:

Refactor MainClock->ClockSettings, providing global BPM, etc.

JerkyTreats

This basically cleans up the faulty assumption of objects sharing a global clock, with the reasonable next-best-thing of sharing global clock settings. Now objects can have a Clock and have BPM/other settings already set.

Nice thing about this approach is that the objects can then overwrite these settings where necessary, without having issues of affecting a global clock.