* Delay call to mongo_client.start_request to first use
* Fix bug that made options set in URI ignored for mongo client initialization
* Use MongoReplicasetClient when option replicaSet option is in MONGO_URI
Merge pull request #10 from lloubiere/master

Open session lazily rather than at each new request
Use MongoReplicasetClient when option replicaSet option is in MONGO_URI