Make App add the mediaTypes used

So other book editors can register different mediaTypes
Removed unused imports

mostly jQuery, Underscore, and Backbone
Fix close tag
Add who last edited the file

For remote-updates and collaborative editing
Fix flexbox for content

Content flexbox is broken (right side to large) when styled like
we do in OERPUB.
Got the right flexbox values with http://demo.agektmr.com/flexbox/
Merge pull request #106 from oerpub/fix-content-flexbox

Fix flexbox for content
Merge pull request #105 from Connexions/weekend

Weekend Updates
Merge branch 'master'

Conflicts:
	scripts/views/layouts/workspace.coffee