Update to RebalanceDataset task. Changed static method interface to one where RebalanceDataset is H2OCounted completely, which can be created and submitted to FJ queue.
Merge branch 'master' of github.com:0xdata/h2o
Moved RebalanceDataset correctly to water/main/java instead of /water/test/...

Added RebalanceDatasetTest testing basic rebalance dataset functionality (just rebalance prostate.hex (380 lines) into 300 chunks and check values of all rows.