Make ongoing ownership transfers in status work.

Accomplished by fixing the mismatch between ownership_handoff &
ownership_transfer atoms. All usages now use
riak_core_handoff:ho_type().  Removed _transfer & _handoff suffixes from
atoms, as they are all a type of handoff.
* Translation functions from hash (integer or binary) to partition ID
  and back. Partition IDs are zero-based up to (but not including) ring
  size.
* For user-facing tools, hash_is_partition_boundary/2 can be used to
  verify whether a hash provided by the user is actually the first
  in a partition.
* EQC and unit tests.
Switch to ordsets to prop_only_boundaries faster. Also allow test to run longer to cover more hash space
Make EQC tests easier to scan
Leverage equals/2 per @seancribbs