Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=55715
Add a per web application executor to the WebSocket implementation and use it for calling SendHandler.onResult() when there is a chance that the current thread also initiated the write

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1537041 13f79535-47bb-0310-9956-ffa450edef68
Fix markup

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1537050 13f79535-47bb-0310-9956-ffa450edef68