Revert PIG-3434: Null subexpression in bincond nullifies outer tuple (or bag)

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1529315 13f79535-47bb-0310-9956-ffa450edef68
PIG-3483: Document ASSERT keyword

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1529318 13f79535-47bb-0310-9956-ffa450edef68
PIG-3483: Document ASSERT keyword

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1529319 13f79535-47bb-0310-9956-ffa450edef68
PIG-3445: Make Parquet format available out of the box in Pig (lbendig via aniket486)

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1529323 13f79535-47bb-0310-9956-ffa450edef68