Device Updates

AnalogTemperatureDevice:

Add shortcuts `tempC` and `tempF` for reading sensor values.

MiniPhDevice:

Change constructor to no longer take a pin (since it's an I2C device).
Instead, you can specify an address. (It defaults to 0x4D)

TSL Device:

Change to a multi-value device. Now returns values for lux, full-spectrum
luminosity, IR luminosity, and visible-light luminosity.

Add shortcuts `lux`, `luminosity`, `irLuminosity`, and `visibleLuminosity`
Add GprsSender and ManylabsDataAuth libs. Update readme.