At first this looked like this could be complicated because I though old installed FFI extensions could be affected ad we'd have to support both name formats, but on closer inspection the bug only exists when computing the development filename, so we can just fix it without having to worry about backward compatibility. Also it looks like this is only an issue with Windows (where filenames with :: would be bad) when the FFI extension doesn't use a .fbx file.
See also #281, which didn't quite get it right.
At first this looked like this could be complicated because I though old installed FFI extensions could be affected ad we'd have to support both name formats, but on closer inspection the bug only exists when computing the development filename, so we can just fix it without having to worry about backward compatibility. Also it looks like this is only an issue with Windows (where filenames with
::would be bad) when the FFI extension doesn't use a.fbxfile.