CAY-1912 BatchQueryBuilder refactoring

git-svn-id: https://svn.apache.org/repos/asf/cayenne/main/trunk@1577910 13f79535-47bb-0310-9956-ffa450edef68
CAY-1915 BatchTranslator instead of performing bindings should return binding object whose values can be altered

git-svn-id: https://svn.apache.org/repos/asf/cayenne/main/trunk@1577911 13f79535-47bb-0310-9956-ffa450edef68