Renamed testAddFloatingTaskWithID (doesn't make sense) to testAddFloatingTask.
Added 2 tests for adding duration and deadline tasks.
Removed unused import in IDonLogic.
Added tests for delete and edit task functionalities.
Added response check in the add task tests.
Merge branch 'master' of https://github.com/cs2103aug2014-w11-2j/main
Changed command type comparisons in DonLogic to work with new command types in IDonCommand.
Added functionality in runCommand for undo to be called.
Added tests for the undo functionality.