Adafruit-circuitpython-gps

* Added support in adafruit_gps.py for GPGLL, GPVTG, GPGSA, and GPGSV NMEA sentences.
* GPGLL - Geographic Position – Latitude/Longitude
* GPVTG - Track Made Good and Ground Speed
* GPGSA - GPS Dilution of Precision and active satellites
* GPGSV - Satellites in view
* Changed the input buffer check 64 bytes in the input buffer to 32 bytes in the input buffer since some sentences aren't 64 bytes.

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-gps`.

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

- Added a check to make sure the number of bytes in the input buffer was at least 64, so the module doesn't block while waiting for bytes in the buffer.
- Added an explanation of NMEA 0183 and the different formats in which the data is transmitted to the microcontroller from the GPS.

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-gps`.

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

Updated Example Timeouts for busio.UART function since it now takes seconds instead of milliseconds and updated associated documentation. Thanks dherrada.

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-gps`.

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

Updated an error in `examples/gps_simpletest.py`.

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-gps`.

Read the [docs](http://circuitpython.readthedocs.io/projects/gps/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-gps`.

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

Added example for using GPS as a RTC.

Added `datetime` property.

Updated example names to match convention.

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-gps`.

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