changing return type from String to Vector<Task>
separate "help" and other commands
Merge pull request #43 from cs2103aug2014-w15-3J/Logic

Merge pull request #42 from cs2103aug2014-w15-3J/master
Merge pull request #44 from cs2103aug2014-w15-3J/master

Merge Logic with Master
Merge pull request #46 from cs2103aug2014-w15-3J/parser

Merge Master with Parser
Merge pull request #47 from cs2103aug2014-w15-3J/Logic

Merge pull request #44 from cs2103aug2014-w15-3J/master
pass the list of tasks in both String and Vector<Task>
Merge pull request #48 from cs2103aug2014-w15-3J/master

Merge Logic with Master
Merge remote-tracking branch 'origin/Logic' into parser