|fname||The file to use.|
|newext||The new extension to use.|
This function returns the indicated file name with the extension
(including the dot) changed to the new extension. By using an empty
string as the new extension you can remove the extension part all
filename_change_ext(file_find_first(working_directory + "*.*", 0),
The above code gets the name of the file (as a string) with the extension part removed.