Adafruit-circuitpython-dotstar

* 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!

* Fix brightness

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 library bundle](https://github.com/adafruit/AdafruitCircuitPython_Bundle).

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

* Rename the module to `adafruit_dotstar` to match other Adafruit libraries.
* Make the API identical to NeoPixel.
* Use hardware SPI when available on the given pins.

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 library bundle](https://github.com/adafruit/AdafruitCircuitPython_Bundle).

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

Bitbanged DotStar support!