Update GWT to 2.5.1
Update GWT to 2.5.1

The 2.5.0 release does not have the necessary dependencies for javax.validation
pjvds/atmosphere-samples,pjvds/atmosphere-samples,ydsakyclguozi/atmosphere-samples,ydsakyclguozi/atmosphere-samples,ydsakyclguozi/atmosphere-samples,pjvds/atmosphere-samples,pjvds/atmosphere-samples,ydsakyclguozi/atmosphere-samples