Removed StreamedRDFIterator in favour of Stephen's PipedRDFStream and PipedRDFIterator, update example to use PipedRDFStream and PipedRDFIterator instead

git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1439817 13f79535-47bb-0310-9956-ffa450edef68