Added bare bone of Mifare Classic diff utility class.
Implemented first diff function for dumps.

(Not tested.)
Implemented second diff function for dumps.

(Not tested.)
Finished documentation of the diff ultis class.
Added bare bone of "Diff Tool"
Created layout for diff tool.
Added missing header.
Filechooser now returns the filename additionally to the full path.
Implemented basic functionality of diff tool.

However, the actiual diff is not implemented yet.
Check dump after reading and before diffing.
Updated diff tools layout to handle different screen sizes better.
Bugfix: converting dump file formats is now working.
Use dips instead of pixels.
Finished the implementaiton of the diff tool.
Merge branch 'diff_tool'
Compare the dump from the editor to another.