eventData » useCapture

I really want ftdomdelegate to be the 'pro' event delegate library therefore I think we should provide a way for developers to be able to decide themselves whether or not to `useCapture` (whilst maintaining the sensible defaults we currently have).

Given we never use `eventData` I propose swapping the fourth parameter of `on` with a `useCapture` boolean.

Obviously this will be a major version bump.

Among other things it would allow me to remove the hacks I had to add in **Selective FastClick** - https://github.com/matthew-andrews/selective-fastclick/pull/1/files.

Spamming: @mattcg @georgecrawford @rowanbeentje @wilsonpage @orangemug 

(Note - I haven't written any tests specifically for this change as I wanted to bounce it as an idea off ya'll first)