Public: Add default validators for the standard constraints.
Include super source version of the Pattern constraint
that does not reference java.util.regex.Pattern

Review at http://gwt-code-reviews.appspot.com/735801

Review by: rjrjr@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@8491 8db76d5a-ed1c-0410-87a9-c151d255dfc7