Device Type and Value support
Version 2.1 adds support for type() and value() functions.
Device.h defines a DeviceType enum that is used to declare the type of device (eg. DeviceType::Light).
The value() and type() functions are pass the String name of the device, and return an int identifying the current value, enum type, or -1 if error.
This support is needed to improve the Alexa skill, and for implementing the SmartThings device handlers.