Removed dependence on INITIAL_PARTITION_COUNT from Malhar

       * Removed dependence on INITIAL_PARTITION_COUNT from Malhar
       * Added StatelessPartitioner to be used for default partitioning
       * Tested all demos/benchmark/test apps with new default partitioner

For some reason the operator used here cannot be copied using a default Kryo instance. It took me a while to debug, so I added a test to make it easier in the future.