Thanks to ladyada for adding a warning comment that the DATA line must be pulled up.
To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).
To use in CPython, `pip install adafruit-circuitpython-ds18x20`.
Read the [docs](http://circuitpython.readthedocs.io/projects/ds18x20/en/latest/) for info on how to use it.