Adafruit-circuitpython-dotstar

* 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!