Fix `mvn gwt:run`
Fix `mvn gwt:run`

manolo/gwt-api-generator,florian-f/gwt-api-generator,manolo/gwt-polymer-elements,manolo/gwt-api-generator,florian-f/gwt-api-generator,vaadin/gwt-polymer-elements,vaadin/gwt-api-generator,vaadin/gwt-api-generator