mock library for testing

[2bndy5]

I created a new library called CircuitPython-mocks which should allow collecting code coverage (and establishing expected code behavior) during soft-tests of Circuitpython-based projects.

Currently, the SPI, I2C, UART, and DigitalInOut classes are mocked (along with some dummy pins in a mocked board module). I'm interested in adding mocked PWM functionality, but first I was hoping to see if it is worth my time by gathering community feedback.

[dastels]

That's awesome!