Refactor to add support for Circuit Playground Bluefruit

[kattni]

This is a complete refactor to include support for Circuit Playground Bluefruit. I have created a new bluefruit.py for the CPB and circuit_playground_base.py for all the common code. As well, I have included two new features into the bluefruit module: sound_level and loud_sound. These were desired features for the express module but were never included due to memory constraints on the CPX, an issue not currently present on the CPB.

There is no plan for this to be included in 4.x. There is no change to how the express module works which is what is included in 4.x, and therefore there is no reason to update the build.

Once the BLE/CPB-specific CircuitPython code is finalised, I will look into what features should be added here. This refactor was done with that intent in mind.

Change log:

• Removed 3.x CircuitPython checks
• Fixed typos
• Created bluefruit.py for CPB
• Moved all common code to CircuitPlaygroundBase class
• Refactored audio code to work in the base class
• Changed touch_A7 to touch_TX in the base class to match the Bluefruit silk (No pad A7), and added alias to express (CPX has both TX and A7 on the silk) so all current code continues to function the same. You can call touch_A7 or touch_TX using the express module.
• Added sound_level and loud_sound features to bluefruit module
• Documented all features for CPX and CPB in base class
• Sphinx updates.

Example use on Bluefruit:

from adafruit_circuitplayground.bluefruit import cpb

cpb.pixels.fill((0, 255, 0))

Express usage has not changed.

I have attached a 5.x Circuit Playground Express CircuitPython build with this library frozen in - the bluefruit module is not included as it will not be included when this refactor is released. To test, double-tap the reset button on your Circuit Playground Express to enter the bootloader, and drag the CPX_refactor_build.uf2 to the CPLAYBOOT drive.

CPX_refactor_build.uf2.zip

[ladyada]

@dhalbert please review

[jepler]

I didn't test anything but the audiopwmio part makes sense to me.

[dhalbert]

Thanks! Compared Base class with previous version of library. Comparison looks good. I know you tested in real life.

Next step (I will do) is to handle the dummy version of bluefruit.py and freeze that version into CPX.