Add a provider to handle replicaset creation

- Can initiate a replicaset if not initiated
- Can add members to an existing replicaset
Fix the documentation about waiting for mongod
Remove eNovance copyright due to CLA

Remove eNovance copyright as having signed the CLA grants the copyright
to PuppetLabs.
Merge pull request #82 from enovance/fcharlier/replicaset

Add a provider to handle replicaset creation