Speedup _renderComboItems batch html rendering

Speedup _renderComboItems, because the browser won't render on each item.
At the end the whole tree will be rendered. 
Also the click en mouseover events are binded using delegated events.
This makes a lot faster.

This however makes the component dependent on jQuery >= 1.7, because of the "on" function used.

Based on something like this: http://www.devcurry.com/2011/10/jquery-add-elements-dynamically.html

My suggestion list is 4019 items long currenty. This makes it a lot nicer to handle.