Folder url needs to keep 1 forward slash on unix/linux, and lose it if on Windows

[CaelCoruscare]

file:///Users/cael/photos -> /Users/cael/photos

file:///C://Users/cael/photos -> C://Users/cael/photos

This must be a common issue. Surely other people on the internet have run into this. There's probably a better solution than testing for what the operating system is.

[CaelCoruscare]

@toby, I made this because your fix for Windows broke the app on Mac. Turns out 'Users/cael/photos' does not actually work. You need the preceding forward slash.

[CaelCoruscare]

Maybe looking for a ':' at folderURL[1], after removing the QT 'file:///' part would work?

[CaelCoruscare]

@tobykestrel , I've set up a unit test case called "test_cleanURL". Please move the URL cleaning code from SlotBridge.FolderChosen() to ImageExtractor.cleanURL() and use the Unit Test to confirm.