Test case for connection pooling issue
Removed session requestStart, requestEnsureConnections, and requestDone from all MongoClientImpl calls.  Refactored pooling of MongoClients to use Mongo.Holder.  Removed configurable properties related to WriteConcern, in preparation for the 2.12.0 Mongo client.
Add consistent request processors so that users can start and end consistent requests
documentation
Changed schema version in flows to current