Adafruit-circuitpython-circuitplayground

This updates `requirements.txt` so that the Adafruit Learn System Project Bundle includes the appropriate files needed for the examples to work on Circuit Playground Bluefruit.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

Read the [docs](http://circuitpython.readthedocs.io/projects/circuitplayground/en/latest/) for info on how to use it.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

Read the [docs](http://circuitpython.readthedocs.io/projects/circuitplayground/en/latest/) for info on how to use it.

THIS IS A BREAKING CHANGE. It removed `were_pressed` from the library. If your code uses it, consider simply polling for the button presses, or using the [`keypad`](https://circuitpython.readthedocs.io/en/latest/shared-bindings/keypad/index.html) module.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

To use in CPython, `pip3 install adafruit-circuitpython-circuitplayground`.

Read the [docs](http://circuitpython.readthedocs.io/projects/circuitplayground/en/latest/) for info on how to use it.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

To use in CPython, `pip3 install adafruit-circuitpython-circuitplayground`.

Read the [docs](http://circuitpython.readthedocs.io/projects/circuitplayground/en/latest/) for info on how to use it.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

To use in CPython, `pip3 install adafruit-circuitpython-circuitplayground`.

Read the [docs](http://circuitpython.readthedocs.io/projects/circuitplayground/en/latest/) for info on how to use it.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

To use in CPython, `pip3 install adafruit-circuitpython-circuitplayground`.

Read the [docs](http://circuitpython.readthedocs.io/projects/circuitplayground/en/latest/) for info on how to use it.