[#5571] Added akismet and pymollom to requirements-optional.txt

Signed-off-by: Cory Johns <cjohns@slashdotmedia.com>
[#6208] add unique index to wiki app_config_id+title
[#6208] Bumped Ming version for background reindexes

Signed-off-by: Cory Johns <cjohns@slashdotmedia.com>