Changed usage of ArrayList to ObservableList.
Changed usage of Task to ModelTask.
Added Search command in OOP
Date Standardizer classes added
Added MarkDone command in OOP
Merge remote-tracking branch 'origin/jiashun'
Edit TaskList to ObservableList
Edit TaskList to use ObservableList instead of ArrayList.
Merge remote-tracking branch 'origin/krystal'
Added Undo command in OOP
edit
Edit Undo constructor.
Added Redo command in OOP
Fixed index.
Fixed index.
Added Add task at position
Fixed index
Added Move command in OOP
removed unnecessary catch statement
Removed ArrayList components
added class Storage. use storage to load from file and save to file
edited Task class to enable program to scan from textfile and convert everything to observblelist
added ModelTaskToSaveStringConverter to convert a modeltask to string for saving to file.