Adjust the architecture diagram

Some modifications of the architecture diagram:

1. adjust the order of authz and authn; since the API server usually first authenticate user, if it is a valid user then authorize it
2. adjust the arrow to point to kubelet instead of to node of the second node
3. change `replication controller` to `controller manager(replication controller etc.)` which connects to the REST API Server
4. some tiny adjustments of the arrow position
5. affected files: architecture.svg, architecture.png and architecture.dia

Author: hw-qiaolei