PIG-3457: Provide backward compatibility for PigStatsUtil and JobStats

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1524532 13f79535-47bb-0310-9956-ffa450edef68
Merged latest trunk changes to tez branch


git-svn-id: https://svn.apache.org/repos/asf/pig/branches/tez@1525017 13f79535-47bb-0310-9956-ffa450edef68
PIG-3367: Add assert keyword (operator) in pig (aniket486)

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1525045 13f79535-47bb-0310-9956-ffa450edef68
PIG-3410: LimitOptimizer is applied before PartitionFilterOptimizer - missing files (aniket486)

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1525096 13f79535-47bb-0310-9956-ffa450edef68
PIG-3199: Provide a method to retriever name of loader/storer in PigServer

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1525162 13f79535-47bb-0310-9956-ffa450edef68
PIG-3199: Provide a method to retriever name of loader/storer in PigServer

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1525163 13f79535-47bb-0310-9956-ffa450edef68
PIG-3471: Add a base abstract class for ExecutionEngine (cheolsoo)


git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1525165 13f79535-47bb-0310-9956-ffa450edef68
Merged latest trunk changes to tez branch


git-svn-id: https://svn.apache.org/repos/asf/pig/branches/tez@1525170 13f79535-47bb-0310-9956-ffa450edef68
PIG-3448: Tez backend layout (cheolsoo)


git-svn-id: https://svn.apache.org/repos/asf/pig/branches/tez@1525177 13f79535-47bb-0310-9956-ffa450edef68
Merge remote-tracking branch 'apache/tez' into tez-wip