Adafruit-circuitpython-ds18x20

Thanks to sommersoft and kattni for updating the README.

To use in CircuitPython, download the .mpy file and copy it to the `lib` folder on the `CIRCUITPY` drive. Or, simply install the [Adafruit CircuitPython bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle).

Read the [docs](http://circuitpython.readthedocs.io/projects/ds18x20/en/latest/) for info on how to use it.

Thanks to sommersoft for the great work!

Thanks to brentru for the great work!

Initial release to trigger mpy generation with Travis CI.