This change appends the list dir and project root dir to CMAKE_MODULE_PATH so that it doesn't need prepended to each "include" directive.
All .mk files have been deleted, since these are completely redundant.
Removes i2c_inst_t from constructors since it's ignored, and updated the Python bindings not to supply this argument. Instance is inferred from the supplied pins.
Removes all driver-specific SDA/SCL pin definitions and defaults.
Pin type is "uint" everywhere, but "PIN_UNUSED" is *int*_max for MicroPython compat. That's still a lot of pins!
Adds baudrate to the I2C class, and allows a driver (like Trackball) to check the baudrate is supported
Phil Howard
ZodiusInfuser