Switching to WSS4J 2.0.0-SNAPSHOT

git-svn-id: https://svn.apache.org/repos/asf/cxf/trunk@1557186 13f79535-47bb-0310-9956-ffa450edef68
Potential NPE fix

git-svn-id: https://svn.apache.org/repos/asf/cxf/trunk@1557187 13f79535-47bb-0310-9956-ffa450edef68
Added a streaming XML Security in-interceptor for JAX-RS endpoints + tests

git-svn-id: https://svn.apache.org/repos/asf/cxf/trunk@1557188 13f79535-47bb-0310-9956-ffa450edef68