[BUG] Selecting a single file after loading many marks all the files as modified

[ThePromidius]

Describe the bug Selecting a single file after loading many marks all the files as modified

To Reproduce Steps to reproduce the behavior:

1. Open many files
2. Click on one single file as to only modify that one
3. See how the rest of the files get marked as modified

Expected behavior No files get marked as modified

Dev comments

• This issue comes along with a refactor of the comicinfo classs
• One of the issues is that when parsing UI to cinfo the ui returns -1 but original cinfo has "". This marks it as modified.