Transformer: Formal mode toolbar improvements

Summary:
 * Changed the text on the formal mode toolbar to better indicate
   that you are adding transformations to the list
 * Added some icons to the toolbar
 * Move the toolbar below the transformation list in formal mode
 * Add text in formal mode to indicate what to do
 * Add text note in formal mode without movement that the shapes
   won't move

Test Plan:
 * Make a transformer
 * Add and remove some transformations
 * Repeat for all four modes

Reviewers: alex, khirasaki

Reviewed By: alex

CC: alpert, eater

Differential Revision: http://phabricator.khanacademy.org/D5910