Make custom events work on Android 2.3 as well.

Oh Android 2.3, why do people still use you?  You expose a createEvent
method, but throw an exception when I try to use it.  Whatever happened
to feature detection?

So, we end up with another try/catch block where the catch is ignored.
Fire CustomEvent before firing internal event

This gives in-page event handlers the ability to manipulate what goes
onto the beacon or timers before the plugins run.