Bug fix for NULL data in table when using sql2rdd/TableRDD.
Data returned as java objects or "null" values- previously the Scala objects could not represent "null".
Lines less than 100 chars.
Merge pull request #85 from jhartlaub/bugfix

Bug fix for NULL data in table when using sql2rdd/TableRDD (SHARK-119)
Added HiveStructSerializer to serialize data rows.