Backbone 1.0.0, Underscore 1.4.4

The scss junk comes from trying to sync w/ several branches. I believe
it's right but mostly unnecessary (surprised it showed up).
Debugged the merge w/ cms-master
Fixed grace period to be absolute time difference not a date on the
client side.

Move vendor javascript into common/static/js/vendor, so that they can be shared between the CMS and LMS, and create an html template that includes all of the vendor js needed for the courseware