Update en.json

Add missing system message (see issue https://github.com/SemanticMediaWiki/SemanticMediaWiki/issues/181)
Update qqq.json

Add system message description (See issue https://github.com/SemanticMediaWiki/SemanticMediaWiki/issues/181)
Merge pull request #506 from SemanticMediaWiki/i18n-188

I18n 181