Documentation for batching and tokens authenticate

Update examples for batching support and token based authentication.

README.md

@@ -23,6 +23,21 @@ payload = Payload(alert="Hello World!", sound="default", badge=1)
 topic = 'com.example.App'
 client = APNsClient('key.pem', use_sandbox=False, use_alternative_port=False)
 client.send_notification(token_hex, payload, topic)
+
+# To send multiple notifications in a batch
+Notification = collections.namedtuple('Notification', ['token', 'payload'])
+notifications = [Notification(payload=payload, token=token_hex)]
+client.send_notification_batch(notifications=notifications, topic=topic)
+
+# To use token based authentication
+from apsn2.credentials import TokenCredentials
+
+auth_key_path = 'path/to/auth_key'
+auth_key_id = 'app_auth_key_id'
+team_id = 'app_team_id'
+token_credentials = TokensCredentials(auth_key_path=auth_key_path, auth_key_id=auth_key_id, team_id=team_id)
+client = APNsClient(credentials=token_credentials, use_sanbox=False)
+client.send_notification_batch(notifications=notifications, topic=topic)
 ```
 
 ## Further Info