Improved the speed of the comet and chase (marquee) animations by eliminating expensive operations. Thanks jepler!
To use in CircuitPython, simply install the [Adafruit CircuitPython Bundle](https://circuitpython.org/libraries).
To use in CPython, `pip3 install adafruit-circuitpython-led-animation`.
Read the [docs](http://circuitpython.readthedocs.io/projects/led-animation/en/latest/) for info on how to use it.