Apply event delegation throughout? (Allows us to optimize the column headers, etc.)

[GerHobbelt]

• enables virtual rendering of column headers and when you have more than 10/20 of those, this becomes a requirement for performance reasons alone.
• now we already have a lot of (sort-of-hacky) code on board to catch all events, where we catch them again at the container level, because we found over the years that some just don't make it into our handlers otherwise...
  • end result: mouse click events in columns get fired twice when you're unlucky -- and most of the time, you are

See also: http://learn.jquery.com/events/event-delegation/

As we do not support old jQuery libs, we can safely work with the event delegation as coded in latest/modern jQuery.

This does require all plugins to behave nicely as I seem to recall some grave issues with delegated events versus on-node events when it comes to event priorities (inversion/semi-random) as delegated events (of course) come later in the hierarchy chain. (That's what I mean with 'nice behaviour': when we switch SlickGrid to using delegated events, everybody involved must run with it. Hence all plugins used should adhere to the event scheme used by SlickGrid itself.

TO BE RESEARCHED FURTHER.