PIG-3503: More document for Pig 0.12 new features

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1529514 13f79535-47bb-0310-9956-ffa450edef68
Add missing License Header

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1529524 13f79535-47bb-0310-9956-ffa450edef68
Include test-log4j.properties in release

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1529552 13f79535-47bb-0310-9956-ffa450edef68