Minor fixes to ModelUnits.
Testing sorting from TodoItemList.
Merge pull request #200 from cs2103aug2014-w13-1c/jolly/gui

restructured commandcontroller and implemented undo/redo
Fixed settingsView to show the current directory path at launch
Merge pull request #201 from cs2103aug2014-w13-1c/jin/gui

Fixed settingsView to show the current directory path at launch
Fixed ModelUnits
Model has support for randomColorsEnabled and notificationsEnabled now. Haven't tested yet.
Merge branch 'staging' into dat/model
Passed all ModelUnits tests. See model.md for details of randomColorsEnabled and notificationsEnabled.
Merge branch 'staging' of https://github.com/cs2103aug2014-w13-1c/main into jolly/gui