added the feature od UserInterface to change the color of the tasks by their categories, and I changed ITask and Task because their getCategory() method returns String. Maybe you guys using that in Controller or somewhere, they started to put an error message to the console. Please get it fixed!
fixed the issue of JLabel and added the function of clearing all of the lines on the screen.
Merge pull request #19 from cs2103aug2014-f10-4j/working

Shotaro's work on UI - merge to master
Refactoring?
Removed traces of UML Diagram plugin
Merge pull request #20 from andhieka/working

Refactoring from Andhieka
Conflict resolution with master
Merge branch 'liafailboy-working'
Merge pull request #21 from andhieka/master

Merge Shotaro's work
Prepare for next sprint
UserInteface has the feature of the category colors!
Conflicts:
	src/list/Controller.java
	src/list/IUserInterface.java
	src/list/UserInterface.java