Adafruit-circuitpython-dotstar

- Added `setup.py`
- Added PyPI release info to `.travis.yml`
- Updated `requirements.txt`
- Added a more comprehensive `.gitignore`

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle).

To use in CPython, `pip install adafruit-circuitpython-dotstar`.

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

1. The `math` library may not always be available, so uses of `math.ceil()` were replaced with equivalent calculations.
2. `fill()` was sped up by about 25% by using `range()` instead of `enumerate()`.

Thanks to mcscope for the great work!

Thanks to sommersoft for the great work!

Thanks to kattni for fixing a rogue neopixel reference and a missing import.

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The files in each release are compiled for all recent major versions of CircuitPython. Please download the one that matches your version of CircuitPython. For example, download the bundle with `2.x` in the filename for CircuitPython versions 2.0.0 and 2.1.0.

To install, simply download the matching zip file, unzip it, and copy the lib folder onto your CIRCUITPY drive. If `lib` already exists, make sure to merge into the directory instead of replacing the whole thing.

* The brightness setting did not work properly in some cases.
* Using `__getitem__()` with slices (e.g., `values = dotstars[5:30]`) had an error.

To use in CircuitPython, download the `adafruit_dotstar.py` file and copy it to the `lib` folder on the `CIRCUITPY` drive. Or, simply install the Adafruit CircuitPython library bundle when it's updated to include this release.

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

Thanks to bodger in the Adafruit forums for finding problems and testing the fixed version!