Hw4

Dear Instructors,

Sorry I pushed a few confusing commits several days ago. Please ignore them and just check out Homework 4 I pushed today.

Please kindly take a look at both of the RMD fie and the Working PLUNK:
http://plnkr.co/edit/87WLm3OmK1jRtcq8p96u?p=preview

Thank you very much!

Yan (Emily)