fix problem "unable to resolve class com.vaadin.grails.VaadinConfiguration" on first time compilation.
Described into https://vaadin.com/wiki/-/wiki/Main/Vaadin+on+Grails+-+Create+project+in+IntelliJ+IDEA
Merge pull request #35 from zhuravskiy/fix-Events

fix problem "unable to resolve class com.vaadin.grails.VaadinConfiguration"