updating tutorials to match 3.2 APIs

git-svn-id: https://svn.apache.org/repos/asf/cayenne/main/trunk@1486471 13f79535-47bb-0310-9956-ffa450edef68
CAY-1724 Add 'Property' class for easier and better Expression creation

must use client class name for the rel target

git-svn-id: https://svn.apache.org/repos/asf/cayenne/main/trunk@1486472 13f79535-47bb-0310-9956-ffa450edef68