* this patch was contributed by "imyrek"
 * http://sourceforge.net/tracker/?func=detail&aid=3054257&group_id=237831&atid=1104178


git-svn-id: https://pycam.svn.sourceforge.net/svnroot/pycam/trunk@656 bbaffbd6-741e-11dd-a85d-61de82d9cad9