Fix updating of last access time, add tests for event handling

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/jcs/trunk@1581516 13f79535-47bb-0310-9956-ffa450edef68
Update docs

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/jcs/trunk@1581517 13f79535-47bb-0310-9956-ffa450edef68