Adding support for application launch using DIAL when installed on FireTV devices.

This allows Concerto TV to be launched from other devices on the same network.
Note: "Concerto" has been registered in the DIAL Registry for Concerto Signage applications.
Keep device screen on while Concerto TV is running.

Set main activity window to always keep the screen on.
Merge pull request #15 from concerto/firetv

Add support for Amazon Fire TV.