Removed dependence on INITIAL_PARTITION_COUNT from MALHAR

   * Removed dependence on INITIAL_PARTITION_COUNT from MALHAR.
   * Added StatelessPartitioner to be used by operators which want a default partitoner which creates multiple partitions.
The following property was set in test()

conf.set("dt.operator.Store.attr.INITIAL_PARTITION_COUNT", "2");

I should be setting the partitionCount here, will update.