This **breaking** release adds:
* Updated SMS receive mechanism
* Added Ring Indicator (RI) pin to fona initialization.
* Move to polling `receive_sms` mechanism instead of only polling the serial UART.
* `receive_sms` allows for optionally checking UART or RI for incoming SMS messages.
* Examples (`sms` & `sms_response`) updated
* **BREAKING**: Removed public access to uart serial functions (readline, uart write) from user-code
* Added compatibility for FONA3G Modules:
* New `fona_3g.py` child class, contains methods compatible with the SIMCom SIM5320 module's AT command set.
* `adafruit_fona_socket` queries and uses the SIM5320's tcp transmit timeout, socket writes now use user-set timeouts
* Examples updated and tested with FONA808 and FONA3G
* **Breaking**`adafruit_fona_network` class added for connecting and interacting with GSM and CDMA cellular networks.
* Note: This replaces the `GSM` class.
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-fona `.
Read the [docs](http://circuitpython.readthedocs.io/projects/fona/en/latest/) for info on how to use it.