Update padding for content in folders
Return a default mediaType if none is matched
Remove an internal Node when dropped

instead of making a copy
Dropping a Folder on a Book now works

Also, the draggable Model is stored on the jQuery element insteaad of
being looked up
Advanced button only shows on hover
Improved sidebar DnD and hover styling
Added colors to content types and changed expando buttons
Removing special case code for organizational book nodes
Moved CSS file to LESS file, added icon for container
Refactored to use nested selectors
More cleanup in the CSS
Delays drop event so jQuery can clean up before DOM changes
Dereferencing pointers works
Dragging a Folder in a Book now registers all dropped children
Sidebar tree loads faster for large books

Node children are lazily parsed into ItemViews instead of (re)rendering
the whole tree and then hiding nodes.
Removed extra view redraws

caused some elements to show up twice
Fixed "dirty bit" when saving

Enabling the "Save" button should work properly and unsaved content
should be visually marked as such.