Reduce visibility

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1618832 13f79535-47bb-0310-9956-ffa450edef68
Rename to align with RFC 6455 terms

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1618833 13f79535-47bb-0310-9956-ffa450edef68
Add rsv to MessagePart and re-order constructor to match order elements
are used in RFC 6455

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1618834 13f79535-47bb-0310-9956-ffa450edef68