Log Message:
py-markdown2: updated to 2.4.9

python-markdown2 2.4.9

- Add `<thead>` tag to html-classes extra
- Fix link patterns extra matching against internal hashes
- Replace deprecated `optparse` with `argparse`
- Fix `_uniform_outdent` failing with empty strings
- Fix HTML elements not unhashing correctly
- Remove deprecated `imp` module
- Allow link patterns to be passed via extras dict
- Fix relative links not working in safe mode