Reworked the section about properties configuration in the user's guide.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1599341 13f79535-47bb-0310-9956-ffa450edef68
JavaDoc

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1599342 13f79535-47bb-0310-9956-ffa450edef68
TAB policy

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1599343 13f79535-47bb-0310-9956-ffa450edef68