JavaScript-highlight connected inputs/outputs

In the pipeline edit form (ui/transformations_ui.pipeline.edit.inc), it's currently a bit hard to recognize which inputs are connected. Lacking a nice canvas-based interface a là Yahoo! Pipes, I tried to work around the most serious problems by color-coding similar inputs. That works to a certain point, but is still not totally usable.

A feasible idea to improve the current interface would be a JavaScript connection hint: when the mouse moves over a connected input, the corresponding output should be highlighted (maybe in the same orange hue that appears when the button is actually clicked). Same for outputs that cause corresponding inputs to be highlighted.

One way to implement this approach would be to store the connected other side along in a CSS class (e.g. ".connected-TfNodeLoad-1"), assign an appropriate id tag to each connection button, and have the JavaScript assign the highlight color (currently '#ffee99') to the corresponding button. When the mouse leaves, the color would be removed again.