Updated the link to the RTD documentation in the README.
To use in CircuitPython, simply install the [Adafruit CircuitPython Bundle](https://circuitpython.org/libraries).
To use in CPython, `pip3 install adafruit-circuitpython-ble-beacon`.
Read the [docs](http://circuitpython.readthedocs.io/projects/ble_beacon/en/latest/) for info on how to use it.