added editListener which will listen to the text input field change.
if you type "edit 2" it will show 2nd task description.
Merge remote-tracking branch 'origin/krystal'
Merge remote-tracking branch 'origin/yongkai'
corrected the editlistener bugs. now the listener only listen to change once per enter key press
Bug fixing.
Added dash date support.
Merge remote-tracking branch 'origin/jiashun'
Fixed adding empty and null Strings.
Tray Functionality
Fixed editing empty and null Strings.
Merge remote-tracking branch 'origin/jiashun'
Merge branch 'master' of https://github.com/cs2103aug2014-t11-1j/main into krystal
Make todayview work. "show today" for todayview, "show all" for all view