MicroPython I2C general TODOS

[Ivan-Velickovic]

• Handle large requests/split up requests.
• Check that we're releasing the I2C bus when we get an error
• Handle multiple busses better, right now the machine_i2c.c code makes some assumptions about only talking to one I2C device driver/sub-system.
• Document what sub-section of the I2C API we cover (e.g machine_i2c.c only provides I2C transfer to MicroPython but not sure if that gives access to all APIs to users).
• Implement machine_i2c_print?
• Add a script for testing I2C functionality?