Adding support for setting a Signature Derived Key Length for the DOM code

git-svn-id: https://svn.apache.org/repos/asf/webservices/wss4j/trunk@1566589 13f79535-47bb-0310-9956-ffa450edef68
Added some derived key interop tests

git-svn-id: https://svn.apache.org/repos/asf/webservices/wss4j/trunk@1566591 13f79535-47bb-0310-9956-ffa450edef68