Merge pull request #96 from cs2103aug2014-w15-3J/master

Merge Logic with Master
Added validation for the adding of timed tasks (endDate and endTime
cannot be earlier than startDate and startTime). Added validation to
ensure that there are no task duplicates
Added commenting template to codes under logic written by Nicholette
change CMI to KIV
Added comments for logic class
Changed name of TickCMIManager
Merge pull request #97 from cs2103aug2014-w15-3J/master

Merge Logic with Master
Edited isExpired method
Changed to KIV
Implemented getIsExpired()
Changed to KIV in UndoManager
Merge pull request #98 from cs2103aug2014-w15-3J/Logic

Merge Master with Logic