This consolidates all actions to close modals into modals.js and
triggers the correct cleaning/collapsing function dependent on what the
data-overlay attribute is labeled as.
It also ensures these all have an e.stopPropagation().
Fixes#4029.
* Created a drafts modal to display/restore/delete drafts
* Created a Draft model to support storing draft data in localstorage
* Removed existing restore-draft functionality
* Added casper and node tests for drafts functionality
Fixes#1717.