If there's not enough data to calculate a distribution, assume data will have UUID primary keys.
Fix endianness bug.
Merge branch 'reql_admin' into tim/3271-uuid-distribution
Add interface.shard_balancing test and fix some bugs it exposed.
Tweak fudge factors in shard_balancing.py.
Clean up split_points.{hpp,cc}
Fix minor style issues in split_points.cc