Cleaned up Roomie.Common.Device
* Made Network and Location properties public get, protected set.  (This was weird before because the DeviceModel from the API and website extended this class, and I needed to dance around the ORM's requirements.)
* moved Power and MaxPower out of Device.  Now it's always stored in IDimmerSwitchState, which makes the most sense.
* Created an Update method on IDimmerSwitchState.  This updates the state without actually changing devices.  (used for data synchronization.)