WildcardFileFilter move to core request

I thought i'd find this code alongside the File class, but it's in the gui basics module with the filebrowser GUI component, i wanted to use that in a CLI application, i was looking at the code itself and it does not do any GUI stuff, maybe we could move it to juce_core so that it's there with the File class ? Ofcourse the FileFilter class too since it's a base for the WIldcardFileFilter.

Good request! Will do that when I get a moment.