[TIMOB-3310] doubletap zoom for ScrollableView pages

I'm sorry if this has been reported before, I tried searching but couldn't find anything on this specific issue.

Currently, there seems to be no way to allow standard doubletap zooming for elements other than WebViews. I have tried using webviews as ScrollableView elements, but could not figure out a way to enable events on it without disabling the scroll functionality of the scrollableview. Forgive me if I'm overlooking something.

Please implement either:
* A way to enable zooming in (to a preset scale) and zooming out using the doubletap event in ScrollableView (currently, only the pinch-zoom gesture works, but not the doubletap, which is a pretty standard and hence intuitive feature at least in iOS). * A way to set the scale of the current view programmatically, so that we can listen for the doubletap event in the code and implement this action from there. This naturally would need to support animation.

Thanks,
Rene