Grady/reorder

Allows reordering of Assessment Modules in the Settings Tab.  All functionality and styling was stolen from or attempts to imitate studio's use of Sortable.
Another great question!

The placeholder is the area that jquery-ui uses "behind" the dragged element, which snaps into place where it will be dropped if dropped immediately. We can't change that via a CSS style because we don't have a reference to it (and doing so/finding out) would place a huge dependency on the way that JQuery UI implements that feature.

The Item is actually also a complicated story (it is the item that you are actually dragging).  I tried the method of toggling the class name to change the height (which is successful at changing the height), BUT doesn't change the space that it takes up.  SO, the element that you drag if you go with that approach is the correct size visibly, but is not recognized by Sortable, because (even with a refresh/refresh-positions), the internal sortable element does not recognize the new height.  This procedure instead JUST changes the height of the element being dragged as it is seen by Jquery, NOT its actual height.  Through implementation of sortable, those two are distinct.

Or at least that is to the best of my understanding.