Improving valves documentation.
Wrap RemoteAddrValve and RemoteHostValve valves into a distinct section.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1590471 13f79535-47bb-0310-9956-ffa450edef68
Improving valves documentation.
Move RemoteIpValve and SSLValve into new section "Proxies Support".

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1590474 13f79535-47bb-0310-9956-ffa450edef68
Improving valves documentation.
Move valves implementing an Authenticator into new section "Authentication".

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1590479 13f79535-47bb-0310-9956-ffa450edef68