Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=55639
Add a Drawboard WebSocket example.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1530296 13f79535-47bb-0310-9956-ffa450edef68
svn:eol-style = native
Sorry for the noise.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1530298 13f79535-47bb-0310-9956-ffa450edef68