Fixed setting connection type and provided descriptors for getting and setting it. Thanks bablokb!
To use in CircuitPython, simply install the [Adafruit CircuitPython Bundle](https://circuitpython.org/libraries).
To use in CPython, `pip3 install adafruit-circuitpython-esp-atcontrol`.
Read the [docs](http://circuitpython.readthedocs.io/projects/esp-atcontrol/en/latest/) for info on how to use it.