fixed wrong activity reference

There was a bug when opening windows multiple times. `setExtras` only referenced the correct Activity when opening the window for the first time. I removed the global activity reference and now it works fine on every window.

I've also replaced `activity.runOnUiThread` with `TiUIHelper.runUiDelayedIfBlock` which does basically the same job but in a more simple way (without that ugly Looper condition).

Updated to version 1.1.2 incl. .zip