Merge pull request #38 from cs2103aug2014-w15-3J/master

Merging Logic with Master
Impleted tick command
Merge branch 'Logic' of https://github.com/cs2103aug2014-w15-3J/main.git into Logic
Implemented list and help command
implemented help
Added isRepeating attribute to superclass Task
added isRepeating attribute to Task child classes
Implemented date in RepeatingTask
Implemented add RepeatingTasks
Implemented sort for RepeatingTasks
Error in adding repeating tasks with start date. Edited.
Resolved printing error in RepeatingTask
Added space in toString
Merge pull request #39 from cs2103aug2014-w15-3J/Logic

Merge Master with Logic