Updated build to the latest released protobuf jar.  Also made some enhancements to Message so that you can write it to
a stream as a partial or as message.  Doing a partial will allow you to append more messages to the stream and when demarshalled
they will be merged as one message.



git-svn-id: https://svn.apache.org/repos/asf/activemq/sandbox/activemq-protobuf@692498 13f79535-47bb-0310-9956-ffa450edef68