Support onClickCapture and friends

From the react docs:

The event handlers below are triggered by an event in the bubbling phase. To register an event handler for the capture phase, append Capture to the event name; for example, instead of using onClick, you would use onClickCapture to handle the click event in the capture phase.

Should we add support for this as well? I think we can just add the relevant code in HtmlAttrs.scala - Do you see any problems with this?

[jatcwang]

I’m not in dire need of this. I’ll add it to topic/neo branch

[jatcwang]

Here’s a good explanation: http://stackoverflow.com/questions/4616694/what-is-event-bubbling-and-capturing

So onClickCapture that’s bound on a container element will allows you to handle events in the container before the inner elements receives the event. This is useful in many cases when you want to stop propagation of the event to inner elements if some logic determines that you don’t want the inner element to see the event at all.