Add warning about 'hidden' DIRs in the appBase

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1483743 13f79535-47bb-0310-9956-ffa450edef68
Start the addition tests

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1483744 13f79535-47bb-0310-9956-ffa450edef68