f8e23e495b
Finding the extension included hidden files (starting with a '.'), now finding the extension matches Python's `os.path.splitext` behavior which has the advantate a hidden file is not considered one long extension - with an empty name part. Also update code to use BLI_path_extension in cases which previously in-lined this logic. BLI_path_frame_get path argument is now const, it was being manipulated unnecessarily.