Added more logic for mic/listening on off.
1. when app starts, listening is off, tasks disabled.
2. when there are tasks being listened for, listen on unless..
3. ..user manually disables tasks (should remain disabled until enabled
again)
4. when all task alerts have gone off, listening disabled
5. if user manually deselects last task, listening disabled.
5. if user manually enables listening, but does not select tasks and
goes to another screen/background, stop listening and show disabled
screen upon reentry.

I used tasksSelected and userGreyedOut, because I thought
kitchenEventDetector.isDetecting wasn't really based on tasks selected 
(fix if I misread things)
Merge branch 'master' of https://github.com/thisisdhaas/CookEase.git