Ported r25637 from the 3.3.0 tag.
The command used was: svn merge -r25636:25637 svn+ssh://bugman@.../svn/relax/tags/3.3.0 .
..... Python 3 fix for the lib.periodic_table module. The Python string module does not exist in Python 3. .....
Authored by: bugman 2014-09-04
Parent: [r25637]
Child: [r25639]
