Dialogs should not have icon unicodes baked in

[scatterlogical]

File dialogs have the icon unicode characters as string literals - this makes it potentially incompatible with custom fonts.
My first course of action was to inherit a custom class from each of the dialog classes, and thankfully a lot of the methods are virtual, so I can override IconSelector() for starters - but then the menu bar, sidepanel, refresh, all contain unicode literals.
Please provide a virtual method (or virtual properties) to override these unicodes.

[JunaMeinhold]

Hi, i planned on making a static class for setting (virtual has too much overhead) those, but i don't have the energy to deal with it right now, you can make a PR if you want.