CAN support

[dreydean]

Hello, Great work on this library! Just curious, is there any CAN support built in? I haven't been able to find any? Do we need to add that functionality in? Again thank you for your hard work!

[greiman]

I have no experience with CAN and there is no CAN support for Teensy 3.6 in native ChibiOS so I can't commit to adding support since it can't be ported from native ChibiOS.