Bring back one finger zoom

### Is your feature request related to a problem? Please describe. Before version 4.0 you could tap 2 times at the image (e.g. when cropping with selected aspect ratio) and then move the finger to zoom it. I've used this all the time because my phone's multitouch is broken. But in the version 4 when i'm doing the same gesture it only zooms in and you cant zoom out. ### Describe the solution you'd like Bring back the old gesture or make setting to enable it ### Describe alternatives you've considered Switching back to version 3.9