Fixed explanation of the jQuery listener events

The description for YUI's "delegate" and "on" needed some tuning up. jQuery highly promotes their ".on()" as the only way to bind elements. Delegate, bind, live are to be there for only the purpose of backward compatibility.  In some ways, I think we should even remove this whole "explanation" and just place a description here like "Binding a listener event to an element with target elements"  or something like that.