Proper pluralization of member count for orgs.

Updated en locale to do proper pluralization of Members in Organizations show page.
added empty i8n keys for member count for locales that did not already have a top level key called organizations
moved organizations - "member of" string to user and added empty organization member count keys
Merge pull request #527 from steverob/master

Proper pluralization of member count for orgs.
Adding new organization member count