Add genitive and partitive month names and remove hardcoded case
suffixes from predefined date formats. One format incorrectly
had case suffixes added to abbreviated month names.

Removed some redundant "this->", sbergman@redhat.com.

This speeds up importing unicode text a lot. Results of a sample of
chinese text of 5 pages:

- before: 18.351s
- after: 6.692s