Library should support Mongo 3

[mzemmour]

Library should be able to work with Mongo 2 or mongo 3 (I'd suggest to add a boolean/enum argument in the constructor method to select the mongo version )

[mzemmour]

Code should be like:

if (ConfigurationUtil.isUseMongo3Authentication()) { credential = Credential.builder().database(dbName).userName(userName).password(password.toCharArray()).authenticationType("SCRAM-SHA-1").build(); JavaScramSha1Authenticator authenticator = new JavaScramSha1Authenticator(); authenticator.setCredentials(credential);

            config.setCredentials(Lists.newArrayList(Credential.builder().database(dbName).userName(userName).password(password.toCharArray()).authenticator(authenticator).build()));
            //config.getCredentials().iterator().next()
            //config.addCredential(Credential.builder().database(dbName).userName(userName).password(password.toCharArray()).authenticator(authenticator).build());
        }
        else{
            credential = Credential.builder().database(dbName).userName(userName).password(password.toCharArray()).build();
            config.addCredential( credential );
        }
    }

    com.allanbank.mongodb.MongoClient mongoClient = MongoFactory.createClient(config);

    database        = mongoClient.getDatabase(dbName);`