Ability to disable the automatic zoom out when pinch end.

**Is your feature request related to a problem? Please describe.**
I'd like to zoom in very deep in the image, but as the pinch end, the original gets back its original size, so I can't zoom more.

**Describe the solution you'd like**
An option to disable the revert back to original size.
As a bonus, an option to double tap to zoom between scaledToFit and real size (100%).
