validateUserInput modified
temporary tooltip implemented
implemented grouping for the left panel
merge with master
settled the initial design for date
merge with tys-v0.4
priority null pointer fixed
parser.getCommandInfo() throws an exception when invalid user input is entered
Merge remote-tracking branch 'origin/xjy-parser' into sun-v0.4
Merge remote-tracking branch 'origin/xjy-parser' into sun-v0.4
catch invalid command exception