1. Fix issues with dragging multiple items
2. Group dragged items into a new block, irrelevant of their position when first dragged i.e. rows 1,3,5 would be become 1,2,3
3. Maintain position of multiple rows in relation to the first row dragged
4. Support jQuery throttle if it exists: http://benalman.com/projects/jquery-throttle-debounce-plugin/