Adafruit-circuitpython-avrprog

- 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-avrprog`.

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

Thanks to brentru for the great work!

Working examples on writing and verifying firmware to AVR chips such as ATtiny85 (e.g original Trinket/Gemma), ATmega328P (Various Arduinos, ATmega2560 (Arduino Mega 2560 variants)