fork newhaven FT800 library and reimplement as git submodule

[rickyelopez]

The Newhaven FT800 library required a few modifications to work on the stm32 (fortunately, I believe most of these were made obvious by compile-time errors, so should be easy to hunt down).

• Check whether the newest version of the repo works on the steering wheel (be warned, modifications will be necessary)
  • if it doesn't work, make it work
• Fork the the newhaven repo into our organization and modify as necessary
• Re-implement into this repo as a git submodule