Adafruit-circuitpython-ssd1306

- 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-ssd1306`.

Read the [docs](http://circuitpython.readthedocs.io/projects/ssd1306/en/latest/) for info on how to use it.

* Add support for more `framebuf` methods. Thanks to raidancampbell!
* Improve lint and docs. Thanks mrmcwethy !

To use in CircuitPython, download the .zip file and copy its contents to the lib folder on the CIRCUITPY drive. Or, simply install the [Adafruit CircuitPython bundle](https://github.com/adafruit/Addafruit_CircuitPython_Bundle).

Read the [docs](https://circuitpython.readthedocs.io/projects/ssd1306/en/latest/) for info on how to use it.

Some devices (e.g. https://www.adafruit.com/product/938) don't have built-in hardware reset, and need to be reset via a pin. Added reset pin as an optional argument to `SSD1306_I2C()`.

Thanks to deshipu for the great work!

Thanks to mrmcwethy!

Fix for new I2CDevice API. Make sure your [CircuitPython](https://github.com/adafruit/circuitpython) and libraries are up to date!