[feature request] Auto start capture for fullscreen windows

[lokster]

I find it very convenient to be able to automatically start the capture only when there is a fullscreen app running - like a game or video.
On Linux I'm using my own helper script for this purpose - starts the whole hyperion when there is a fullscreen app running, and stops it when there isn't. I just don't see a point in having "ambilight" effects while using the PC for day to day stuff - better just let it display some of the built-in rainbow effects.