Initial Drag and Drop functionality from workspace into a book
Updated file organization, removed glyphicons
Book editor updates when content in it updates
If loading fails trigger the error event
Added Save button and listeners when "dirty"
Changed mediaType to match cnx
Workspace is now a singleton so implementations can hook in easier
Fixed Firebug scrollTo problem
Clean up sign-in/out a bit
New content gets an id ('_NEW:*') so it can be added to a book

When the id updates on save the book updates its reference
Added ability to get the main layout
Added Note to Aloha toolbar
Updated custom layout to work with new version of Marionette
Merged from 'bookish' branch