After discussions with engineering and product management, we've agreed on the following changes:

• The 'yamgo' package will be renamed to 'mongo' (as will the directory name containing the files of that package).
• The 'yamgo.Client' type will be rename to 'mongo.MongoClient' for consistency with other drivers

I think the source file 'client.go' can keep its name and I think we can continue to use 'mongo.NewClient(uri)' as the constructor function for a MongoClient. (Or we can change it to mongo.NewMongoClient(uri)' if we feel that is more idiomatic.)