Adding streaming-based "ut" demo

git-svn-id: https://svn.apache.org/repos/asf/cxf/trunk@1558487 13f79535-47bb-0310-9956-ffa450edef68
StAX-enabling ut_policy sample

git-svn-id: https://svn.apache.org/repos/asf/cxf/trunk@1558488 13f79535-47bb-0310-9956-ffa450edef68
Stax-ifiying ut_sign sample

git-svn-id: https://svn.apache.org/repos/asf/cxf/trunk@1558489 13f79535-47bb-0310-9956-ffa450edef68