This also changes the existing collection functional test to inherit FunctionTestCase

Inheriting from the Client's URI options is not implemented, as it depends on PHPC-196.

This commit also revises the documentation for selectDatabase(), selectCollection(), and the core class constructors.

We can move this to a separate, pedantic test class later.

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