PIG-3244: Make PIG_HOME configurable

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1457151 13f79535-47bb-0310-9956-ffa450edef68
PIG-3194: Changes to ObjectSerializer.java break compatibility with Hadoop 0.20.2

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1457169 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'trunk' of https://github.com/apache/pig into trunk