Adafruit-circuitpython-ina219

- Change internals to use `adafruit_register` for register and bit-field read/write
- Updated table of constants, including fix BusADCResolution values (Issue5), add new values
- Add new properties to access registers (advanced API)
- Update i`na219_simpletest.py` to show some usage of the new properties

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle).

To use in CPython, `pip3 install adafruit-circuitpython-ina219`.

Read the [docs](http://circuitpython.readthedocs.io/projects/ina219/en/latest/) for info on how to use it.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle).

To use in CPython, `pip3 install adafruit-circuitpython-ina219`.

Read the [docs](http://circuitpython.readthedocs.io/projects/ina219/en/latest/) for info on how to use it.

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-ina219`.

Read the [docs](http://circuitpython.readthedocs.io/projects/ina219/en/latest/) for info on how to use it.

- 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-ina219`.

Read the [docs](http://circuitpython.readthedocs.io/projects/ina219/en/latest/) for info on how to use it.

Thanks to sommersoft for the great work!

Thanks to brentru for the great work!