Merge branch 'cdodge/meta-data-cms-editing' of github.com:MITx/mitx into cdodge/meta-data-cms-editing

Conflicts:
	cms/static/coffee/src/models/module.coffee

Fix JSON postback error where the content-type header line can contain more info than just the application/json descriptor. Now we just to a compare on the start of the header value.

Feature/bridger/course grading

removed line from optioninput field formatting

Better fix for trailing slash

New URLs require a trailing slash

Bug/tomg/collapsible hint

Feature/ibrahim/followed threads

Remove commented out block and pull some stuff into a function to load the first page of results for a thread query.

Conflicts:
	lms/djangoapps/django_comment_client/forum/views.py

Match custom static tabs after discussion URLs so that discussion can actually work.

Conflicts:
	lms/djangoapps/courseware/views.py

Feature/victor/static tabs

Fix JSON postback error where the content-type header line can contain more info than just the application/json descriptor. Now we just to a compare on the start of the header value.

adding pkg-config

fix ubuntu graphviz lib install

Properly puluralize comments tooltip and change "unread" to "new".

Show total comments instead of unread only, and use a tooltip to show th...