Re-organised main.java into separate classes:
- Launcher: Contains the public static void main method.
- MainMenu: Contains the application menu loop.
- Main: Contains the actions to perform
- Util: Contains supporting methods
Code refactoring:
- Moved data out of ContactManagerImpl into a separate DataStore class.
- Moved File reading/writing methods out of ContactManagerImpl into a
separate FileIO class.
Added more tests to ContactManagerImplTest
Small bug fix in ContactManagerImpl in adding notes to past meetings
More tests added. Comments updated. Some more refactoring
Code clean up:
- Renaming of some methods & classes 
- Attempts to reduce size of some methods so only ONE action is
performed in each: By splitting into multiple methods.
Updated get meetings to return all future meetings that occur on a
specific date. By only using the day/month/year (not the time) in the
calendar object used as a key in the Calendar/Meetings Map.