Added permission checker.

File dialog checks for permissions required and shows a dialog asking the user if those where not granted yet.

Added permission checker

When using this library with apps, running in Android 11 they crashed. I suspected that missing permissions are the reason. So I added a permission checker.

Improved preview feature.

Fragment's size is now set according to the picture it is displaying. Background color gradient is drawn according to the predominant colors in the picture.

Added locale en

V1.0.1

Added locale en.

First release, have fun.

V1.0.0

Update Readme.md