Updated tablets to use a template in prep for changing them to a
pulldown
Refactored tablets to be generic / independent of Strut.
Styled the new tablets, made surface chooser visible under all modes
"moved" the css and class buttons.  This needs to be revisited.
Allow overflow of slideTable so elements off the grid are still selectable.

This will make it so the contents scroll rather than the editor itself.
Made pulldown toggleable
Created a white markdown icon
Moved responsibility for tablets into the header
Updated tablets to hook into the service registry for their content
Moved button to widgets
Wired all the services together for the new menu area
Merge pull request #216 from KZeni/patch-1

Allow overflow of slideTable so elements off the grid are still selectable
Merge pull request #217 from tantaman/extra-menu

Extra menu
Merge remote-tracking branch 'origin/master' into per-slide-bgs-and-surfaces

Conflicts:
	app/styles/transition_editor/slideTable.css