Added support for Adafruit's Bluefruit

I'm including the code for the protocol, and also I've started a converter for a Model M mod I'm doing; the important code is in the protocol folder, but I'm not sure how to exclude files from the pull request :)

I still need to do a write up on the hardware but it is pretty straightforward.  I still have some features I'd like to add but this is a start for supporting Bluefruit.  Keyboard, mouse keys, and some consumer keys are working (to the extent that they can be supported by Bluefruit 1.2)

Hopefully will have time to update the README in the near future as well, and also add code for switching between USB and Bluefruit based on an input pin