CSHARP-869: stop caching ip addresses.
Spike of adding WriteRequests to the BulkWriteArgs.
Add an invariant to BulkWriteArgs to ensure Requests list is not null.
CSHARP-797: Add Requests to BulkWriteArgs.
CSHARP-797: Changed representation of empty Requests to Enumerable.Empty<WriteRequest>.
CSHARP-915: added MaxWriteBatchSize to IsMasterResult
CSHARP-915: added MaxWireBatchSize to server info.
CSHARP-915: changed MongoServerInstance.MaxWireBatchSize to MaxBatchCount.  Using MongoServerInstance.MaxBatchCount in MongoCollection.
corrected issue with not setting MaxBatchCount in all cases. Also added MongoDefaults.MaxBatchCount.