fix(jqLite): Support unbinding event handler self within handler

If an event handler unbinds itself, the next event handler on the same
event and element isn't run.

This works fine in jQuery, and since jqLite doesn't support `.one()` (to bind handlers that only run once), this
might be a common use case.

I also suggest backporting this to the 1.0.x releases if those are still being maintained.