Adafruit-circuitpython-neopixel-spi

* Update to derive directly from Pypixelbuf

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

To use in CPython, `pip3 install adafruit-circuitpython-neopixel-spi`.

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

* Updated to work with Pypixelbuf based NeoPixel

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

To use in CPython, `pip3 install adafruit-circuitpython-neopixel-spi`.

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

This release includes:
* Migrating this repository from Travis to GitHub Actions. This has no effect on the behavior of the code itself.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://circuitpython.org/libraries).

To use in CPython, `pip3 install adafruit-circuitpython-neopixel-spi`.

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

* Add example code
* Fix 2
* Add mock module to allow use of CircuitPython NeoPixel

* Release for PyPi

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