Redesign of application
Replaced tick label with a checkbox
Fixed bug in CommandController where 'help' and 'settings' doesn't display the respective views. This is because CommandController is attempting to set the backreference to Main for ActionController, but the variable main is still null at that point in time.
Merge branch 'staging' of github.com:cs2103aug2014-w13-1c/main into jin/gui
Merge pull request #192 from cs2103aug2014-w13-1c/jin/gui

GUI redesign
Use one (random) color for all cells
Merge pull request #193 from cs2103aug2014-w13-1c/jin/gui

Use one color for cells + untick icon
changing updateview to show undone tasks by default