Adafruit-circuitpython-rfm69

- 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-rfm69`.

Read the [docs](http://circuitpython.readthedocs.io/projects/rfm69/en/latest/) for info on how to use it.

Minor changes to satisfy pylint. No functional changes

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 bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle).

Read the [docs](http://circuitpython.readthedocs.io/projects/rfm69/en/latest/) for info on how to use it.

Fix frequency setter - add timeout to send.

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 bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle).

Read the [docs](http://circuitpython.readthedocs.io/projects/rfm69/en/latest/) for info on how to use it.

Thanks to sommersoft for the documentation refinement.

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 bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle).

Read the [docs](http://circuitpython.readthedocs.io/projects/rfm69/en/latest/) for info on how to use it.

* Add baudrate kwarg to constructor. Lower baudrates improve reliability when used with the RFM69 breakout. Thanks to jerryneedell !
* Improved docs. Thanks sommersoft !

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/rfm69/en/latest/) for info on how to use it.

Thanks to tannewt for the great work!