Updated Font-Awesome
More improvements to the library browser.
Added a textbook view to the Library Browser and many little bug fixes throughout the Homework Manager.
Got rid of old variables that are no longer used.
Fixed issue #202.
Added answer_date to the calendar.
Added and changed many places to send notifications to the user.
Fixed Issue #198
Fixed Issue #191
The calendar now has a different model underneath and has increased performance.
Beginning of Import/Export of sets.
The Import problem sets is now complete and some minor ui changes.
Merge branch 'develop' of https://github.com/openwebwork/webwork2 into feature/new-ui-tools

Conflicts:
	htdocs/DATA/library-directory-tree.json
	htdocs/DATA/library-subject-tree.json
Bug fixes to the library tree and library browser.
bug fixes and new features for the Textbooks part of the Library Browser.
Fixed textbook section display in Library Browser.
Added a paginator to all problem list views to address issue #203
Fixed Issue #190.
Fixed a general error in that both the date and time wasn't being set correctly.
Continue pulling messages out of the js files and initial switch to backbone 3