Merge pull request #119 from cs2103aug2014-w15-3J/master

Merge Logic with Master
Added more comments
Merge branch 'Logic' of https://github.com/cs2103aug2014-w15-3J/Ticker.git into Logic
Fully commented
added checking for null Vector<Task> for checkForTaskExpiry
Merge pull request #120 from cs2103aug2014-w15-3J/Logic

Merge Master with Logic