CSHARP-816: added MongoDuplicateKeyException.
added doc comments.
Rebased on master.
CSHARP-797: Added maxDocumentSize parameter to MongoInsertMessage.
CSHARP-797: Added maxDocumentSize to more classes. Removed GetNodeAdjustedReader/WriterSettings.
CSHARP-797: Replaced ContinueOnError with Ordered.
CSHARP-797: Removed parts of bulk write results processing that are no longer valid in the most recent version of the spec.
CSHARP-797: Unit tests passing against 2.5.4 nightly.
CSHARP-797: Fixed warnings after rebasing on master.