PIG-3898: Refactor PPNL for non-MR execution engine (cheolsoo)


git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1589784 13f79535-47bb-0310-9956-ffa450edef68
PIG-3905: 0.12.1 release can't be build for Hadoop2

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1589901 13f79535-47bb-0310-9956-ffa450edef68
PIG-3737: Bundle dependent jars in distribution in %PIG_HOME%/lib folder

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1589902 13f79535-47bb-0310-9956-ffa450edef68
PIG-3865: Remodel the XMLLoader to work to be faster and more maintainable

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1589911 13f79535-47bb-0310-9956-ffa450edef68