Adding user model
Use database COMMAND constant
User returns auth key and hashed password
Starting with CR authentication
Shortenting references for shorter lines
Logout using standard method
Remove logout behaviour
Raise exception when unauthorized
Add x509 auth operation, refactor common code
Adding ldap auth support
Use external database name
Change client to require database name on intstantiation
Get strategy for provided options, matching uri options
Connection sets up user and authenticator on instantiation
CR uses hashed password, ldap uses cleartext
Get rid of logout command constant
Automatically authenticate when connection connects the socket and creadentials are provided
Fix comment
Merge pull request #446 from mongodb/authentication

Authentication, Part 1
Skeleton bulk api