Japanese localization

This pull request will
* add Japanese in the Goal.com editions list
* display Japanese edition to users who choose Japanese edition
* display Japanese labels to ja locale users

Note:
I also added lang file for this addon as http://viewvc.svn.mozilla.org/vc/projects/l10n-misc/trunk/add-ons/ja/worldcup.lang?revision=129085&view=markup.