A SupportValidation class to make it easy to define a RPC method
so Hibernate ConstraintViolations are allowed to be serialized.

Review at http://gwt-code-reviews.appspot.com/1443810


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10269 8db76d5a-ed1c-0410-87a9-c151d255dfc7