Working towards clip play position

+ QUANTIZE_MAP, QUANTIZE_NAMES, _quantization

Found update_display() method to override, which Live calls every 100 ms
to update the controller display

Wrote a method to calculate the currently playing beat in a clip, and
called it during update_display()

Need to separate the ideas between beats (of a clip) and steps (of the
sequencer). Right now quantize is set to 1/4 notes, which should mean
each beat is a step --- steps 9-16 do not exist. Adding this to issues.