private void drawablesSelected(List<File> files) {
        Array<FileHandle> fileHandles = new Array<>();
        
        files.forEach((file) -> {
            fileHandles.add(new FileHandle(file));
        });
        
        drawablesSelected(fileHandles);
    }
Called when a selection of drawables has been chosen from the
newDrawablesDialog(). Adds the new drawables to the project.
@param files
core/src/com/ray3k/skincomposer/dialog/DialogDrawables.java