Remove running check from OnStart routine

* for some reason, this is preventing the arpeggiator from restarting when a stop/start signal is sent simultaneously
* gut feeling is that always sees the start before the stop when they are sent at the same time
* removing the check seems mostly harmless, but will need to investigate further
Adding build directory to gitignore
Disabling sh sequencer to save space
Adding preset option to arpeggiator

* adds ability to define presets in the code that can switch the arp direction, octaves, pattern and pattern length with one knob turn
* including five default presets from johnny
* always restarts the arpeggio whenever the preset changes
Adding simple halftime and triplet patterns to pattern list

* this allows us to fake division changes without actually having to change the actual arp divisions, as doing so causes things to go out of sync