Replaced GWT 2.5.1 gwt-servlet.jar with GWT 2.6.0 gwt-servlet.jar as the
GWT installer will load the latest version, GWT 2.6.0 and will be
incompatible with the GWT 2.5.1 gwt-servlet.jar. Note that GWT 2.6.0 has
a bug that prevents the GWT Designer from working correctly but that an
updated version, GWT 2.6.1, that addresses this issue will be released
soon.