Fix #726, add alpha banner, note that this is experimental, and change privacy policy link
Fix #726, add alpha banner, note that this is experimental, and change privacy policy link

mozilla-services/screenshots,mozilla-services/screenshots,mozilla-services/pageshot,mozilla-services/pageshot,mozilla-services/screenshots,fzzzy/pageshot,mozilla-services/pageshot,fzzzy/pageshot,mozilla-services/pageshot,fzzzy/pageshot,mozilla-services/screenshots,fzzzy/pageshot