PIG-2764: Add a biginteger and bigdecimal type to pig (jcoveney)

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1438674 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'trunk' of git://git.apache.org/pig into trunk
Merge branch 'trunk' of github.com:jcoveney/pig into trunk