Add note on testing multicast

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1488139 13f79535-47bb-0310-9956-ffa450edef68
Routing table doesn't show it but it looks like firewall was the only issue.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1488143 13f79535-47bb-0310-9956-ffa450edef68
Fix typos

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1488144 13f79535-47bb-0310-9956-ffa450edef68