Firmware: Add USB command for returning to bootloader

This is necessary for reprogramming a Fadecandy board without access to the physical button.
Firmware config flags for manual control over built-in LED

Sometimes we might want host-side software to control it, or even to just turn it off.
OPC SysEx for sending firmware configuration packets to Fadecandy
Simple Tk UI for setting firmware configuration flags
PyUSB script to reset Fadecandy into bootloader mode
More user-friendly USB serial numbers
Server: Show version number for FC devices
Bump firmware version to 1.1
Update binary for 1.1 release