Improve error reporting for scripts
I have a couple of hundred script-fu scripts most of which have stopped working, provoking an error message on startup, attempted to install a procedure with a full menu path as menu label, this is not supported any longer.
This patch adds the menu label to the error, making it considerably easier to work out which script is causing the problem. It would be better to add also the script-fu filename, but that doesn't seem to be available easily at this point in the code. But the menu label is usually clear enough and is greppable if it has not been translated.errorpatch.txt