Detect inactivity and go into low power mode

[PropaneDragon]

The following features could be introduced:

• Check the TV activity and if there doesn't appear to be anything going on then set the lights back to their previous state and enter the low power mode.
• Allow for a timer to be set where the lights will be active. Anything outside this timer will set the lights to their previous state and enter low power mode.

This would allow the application to be used somewhat headless, without any interaction required.