Remove unused import
Changed from an implementation with two meeting lists (future and past)
to one with a single list, checking for dates when we look them up.

This eliminates the problem of FutureMeetings staying in the future
meeting list when after their date has passed, but it creates other
problems, detailed in the javadoc.
Add tests for past meetings.

Changed the return value of addNewPastMeeting() to match
addFutureMeeting().
Add methods to deal with new past meetings.
Add javadoc to validateContacts helper function.
Make sure that methods that return meeting lists return them in
chronological order.
Add test for adding notes to past meetings.
Add test to avoid adding notes to a meeting in the future.
Fixed test, and added a flawed implementation of addMeetingNotes(), I
can't really figure out what it needs to do.
Forgot to add the test fix.
Add test for flush and read