com.google.zxing zxing 2.2-SNAPSHOT 4.0.0 zxing.appspot.com jar ZXing Appspot-based encoder 2.2-SNAPSHOT GWT-based encoder app hosted at zxing.appspot.com com.google.gwt gwt-user 2.5.1 com.google.gwt gwt-incubator 2.0.1