Improve Meeting Detection

[casaout]

(specification in progress, just capturing ideas)

• Use the microphone to detect (online) meetings (i.e. microphone activated and mute/unmute might be a great proxy for online-meetings; except when someone is recording something)
• an alternative would be to use the calendar
• Refinements
  • refine the retrospection (timeline, top windows)
  • Don't show Self-Reports during Meetings #462
  • IDLE detection
• should this be part of the WindowActivityTracker?