Fix bug 876233: Redirect */about/participate/ -> /contribute/
Bug 934971: activate Lightbeam+webmaker banners on DEV environment for localizers
Bug 892470: add more plugincheck redirects

Have bedrock handle these locales which are deleted on svn:
ak, en-GB, mai, my, nn-NO, nso, oc, sw, ta, ta-LK, ur, wo

These locales won't get updated any time soon and some are not shipped, it's better to fallback to the bedrock en-US plugincheck page than the old mozilla.com one
Bug 930031 - Link to Firefox OS color swatch