When working on Badger I tried to design the interface to be as generic and
applicable as possible: <https://github.com/PMunch/badger/blob/master/i2c.nim>.
The idea is that every platform will have a static I2C object that details
specifics about the platform and exposes one or more such `I2CBus` constants.
Then the rest of the reader/writers takes this static object and uses it to
perform I2C operations. This was used on an Arduino Teensy in a project with a
great focus on small code footprint, so it should be an applicable interface
for pretty much anything.
