[CodeQuality] Fix JS Hint warnings
[Minor] use jQuery as a module dependency
[Minor] shorten function names
[Minor] changed comments

(was trying to use  "pointer-events: stroke" to allow the hovered overlay to trigger a mouseover event which we  could directly use, to call dehover(). But "stroke" seemed to be not allowing clicks etc from within the overlay to be going through as well, hence couldn't be used. TODO: try this later)
[Perf] Minor improvement to areCUsSame
- added check to test direct equality of the references passed
[Fix] Fix minor issue where in some cases the dummy text box is visible on the page (before the stylesheet has loaded it seems)
[Feature] Add module providing basic 2-D directional navigation for CUs, links, etc

i.e., this allows navigation in directions left, right, up, down relative to an element