Added support for fan-in replication topologies, which the replicator
supports by writing data for each replication service to a staging
sub-directory.  Load-reduce-check now uses the correct options to generate
corresponding schema including prepending the service name to the Hive
schema name.  Fixed a bug in the MapReduce sort that caused the merge
between base table and log to add duplicate rows and also ignore some deletes.
Updated README.md to describe current behavior better.