The bulkWrite() method still returns the driver's original WriteResult class. We may change this to use a library-specific wrapper class later.

Add MongoClient and Database objects

As of 0.1.4, driver classes are under the MongoDB\Driver namespace. As of 0.1.5, QueryResult and CommandResult were consolidated into a single Result class.

Rename package to mongodb/mongodb and update metadata

This likely needs to be done for them all?