adds wordcount application
example/50 with NUM_RECORDS=1890 works, but 1891 does not work...
minor fix
istream makes batches not by timespan but by record count
removes log output
removes log output
test works correctly
minor fix
adds RotateSentence
wip: implementing & using PartitionedBatchQueue
partition_by_key is expected to be work...
adds PartitionedBatchQueue
partition_by_key works!
Merge branch 'partition_by_key' into dev