Removed getPastMeetingList from DataInterface - logic now being applied
in the ContactManagerImpl.
Made the getPastMeeting method more generic as doing the casting without
checking in the data layer can cause issues.
Removed all this. from ContactManagerImpl (relic of my Python brain).
Updated getPastMeeting based on testing, now throws if meeting is future
meeting.
Added comments to FutureMeeting methods.
Added getPastMeetingList logic.
Refined tests for ContactManager.
Added test for future meeting list and get meetings, also initialising a
number of meetings before the class to ensure that I know which ones
should be present - creating them per test wasn't consistent.