Merge pull request #44 from matthayes/master

Rename TimeCount to SessionCount
Add missing docs
Add in BagUnion, and cleanup Assert,Coalesce,AliasableEvalFunc
 Changed so that it does not use Tuple's iterator
Merge pull request #45 from evionkim/master

Changed SampleByKey to not use Tuple's iterator
Clean up bag tests

Move pig code into java files.