Use apiserver instead of etcd for kube-proxy.

For cloud-providers that use salt, have kube-proxy use
apiserver instead of etcd as a config source.
- make cadvisor port configurable on the kubelet.
- added cadvisor port documentation.
Added two test cases for KubeletClient
Add python-cherrypy as explicit install for salt-api
Update roadmap based on discussion at contributor meetup.
Scheduler changes for extensibility
Scheduler changes to allow multiple priority functions
Fixing gofmt errors
Combining scheduler priority functions using weighted averages
Implementing PR feedback
 - Making ConfigFactory struct public
 - Added comments for predicate/priority functions and new methods
Implementing PR feedback and adding test cases
Add stack of previous values to converter
produce more readable error messages
refactor to hide structs behind an interface
Use EXIT pseudo-signal
x509 request authenticator
Allow an empty service
Add network testing pod
Make guestbook handle duplicate entries.

Also use kubernetes org on the Docker Hub to host the image.

Fixes #2811
Merge pull request #2450 from smarterclayton/allow_empty_service_selector

Allow an empty service selector