Merge branch 'export_support'
#75 check validity of task when add
#check validity of task when update
Refactored Completer by getting all alias instead
Refactor ANSI Colors to Private
Refactored MenuInterface & Fixed CLEAR cmd
Merge branch 'master' into jLine
Hotfix CommandTest due to change in #75
Merge branch 'jLine'
Fix start date always earlier then end date
Remove startDate if startDate equals EndDate
Merge branch 'master' into pattern_refactor
Refactored HELP command

Now the HELP command is more comprehensive and allows the user to
lookup help on a specific command for more details such as arguments
required.
Created ColorFormatter for application colorcoding
Fixed bug in Task which might lead to an exception

addStartDate is obsolete and can cause exception due to the comparison
done in constructing a new DatePair.
Refactored Command(s) and respective Javadocs
Merge branch 'pattern_refactor'
Reorganize imports in GooManager