Adafruit-circuitpython-simpleio

add an example and also allow float's for tone() frequency, rearrange to be less memory intensive on PWM pins

Thanks to mrmcwethy for the great work!

* Fix `shift_out` so that it actually toggles the clock. Thanks to profbrady
* Fix `simpleio` on boards without `audioio`. Thanks to ladyada

Full change list [from 0.3.0](https://github.com/adafruit/Adafruit_CircuitPython_Register/compare/0.3.0...0.3.1).

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](https://circuitpython.readthedocs.io/projects/simpleio/en/latest/) for info on how to use it.

* Adds Servo to simplify interfacing with servos. Thanks to brentru
* Adds `tone` to match its Arduino counterpart `tone`. Thanks to brentru

Full change list [from 0.2.0](https://github.com/adafruit/Adafruit_CircuitPython_Register/compare/0.2.0...0.3.0).

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](https://circuitpython.readthedocs.io/projects/simpleio/en/latest/) for info on how to use it.

* Removes `NeoPixel` in favor of the separate [NeoPixel library](https://github.com/adafruit/Adafruit_CircuitPython_NeoPixel).
* Adds `map_range`, `shift_in` and `shift_out` to match their Arduino counterparts `map`, `shiftIn` and `shiftOut` respectively. Thanks to asherlie and brentru for them!

Full change list [from 0.1.3](https://github.com/adafruit/Adafruit_CircuitPython_Register/compare/0.1.3...0.2.0).

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](https://circuitpython.readthedocs.io/projects/simpleio/en/latest/) for info on how to use it.

Fourth release for TravisCI generation. Requires CircuitPython 0.9.4!