Add OM of the month link to /othermetas

Add OM of the month link to /othermetas
Add Tier Shift mod for Other Meta of the Month
Merge branch 'patch-8' of http://github.com/Joimer/Pokemon-Showdown into patch-8
Merge pull request #204 from Joimer/patch-8

Add Other Meta of the Month: Tier Shift
April 2013 tier update
Merge pull request #205 from Antar1011/master

Tier Update
Fix Cherish Ball's sprite, shorten Ball descriptions.
Merge remote-tracking branch 'upstream/master'