Upgrade to Selenium 2.31.0
Minor tweak for Spring 3.2 compatibility

Update NavigationMethodOutcomeResolver to use ServletWebRequest as
ServletInvocableHandlerMethod no longer accepts NativeWebRequest in
Spring 3.2
Allow UISelectItemsConverter in saved state

Update UISelectItems.UISelectItemsConverter to be a public static class
allowing it to be saved with component state. The UISelectItems
component is not located by searching children from the getAsString()
method.

Also add new integration test to ensure that the error does not
resurface again in the future.

Issue: 53