* Add a sentence about DDOS.

* Mention problems with low Timeouts and long running CGIs.
* Stress out the experimental character of event MPM and that it does not
  work with ssl currently.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@369902 13f79535-47bb-0310-9956-ffa450edef68