Zen: Return of the alarm warning.

- Remove the term timers from subtitle, the term "alarms"
  is now inclusive of timers.
- Resurrect the alarm warning, give it a more prominent
  appearance if we can detect an overlap in a time-based
  exit condition and the next alarm time.

Change-Id: I5d6d67694c7acc9e2a5a7c63e647069744a22cec