HIVE-7908: CBO: Handle Windowing functions part of expressions (Laljo John Pullokkaran via Gunther Hagleitner)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/cbo@1621374 13f79535-47bb-0310-9956-ffa450edef68
HIVE-7918 CBO:  String Type Conversion, Stats error Propagation, CBO Patch check (John Pullokkaran via Harish Butani)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/cbo@1621408 13f79535-47bb-0310-9956-ffa450edef68