Choose animations over serial interface

[cibomahto]

It would be useful if the serial interface for the BlinkyTape controller allowed for the system state parameters- brightness, and current pattern- to be modified, in addition to supporting patterns streamed from the computer. The use case is to allow specific animations to be uploaded using PatternPaint, then selected by a script running on a computer.

[cibomahto]

A straightforward implementation would be to copy the serial loop protocol from BlinkyTile:

https://github.com/Blinkinlabs/BlinkyTile/blob/master/firmware/serialloop.cpp