HIVE-8016 CBO: PPD to honor hive Join Cond, Casting fixes, Add annotations for IF, Code cleanup (Jojn Pullokkaran via Harish Butani)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/cbo@1623457 13f79535-47bb-0310-9956-ffa450edef68