moving object cache to connection level - adding ObjConn, ObjTask, results list,
added an object cache to avoid duplicating parent objects
made ParentObj mutable; using setEntity instead of creating new object
parent record with all null values (left join with no match) should be left null
added REUSE_STMT flag and related arg
removed LIMIT and OFFSET flags (always supported), added IS_CLOSED flag,
added a way to set type converters based on db column type name;
added getConnection and getResultSet (for underlying jdbc objects),