* Update links to outdated user-guide and admin docs
* Add script for updating outdated links.
* Update regex to include init-containers file.
* Pull upstream, rewrite links in and to namespaces walkthrough.
* hitting the `ClusterIP` from a pod
when client pod and server pod in the same node,client_address is the client pod ip address
when client pod and server pod in different node,client_address is the client pod's node flannel ip address
* Update source-ip.md
* Update source-ip.md