Don't assume every AWS VPC has tags

The default VPC has no tags (by default), so we should use get()
Default ENABLE_CLUSTER_MONITORING to false

Otherwise kube-down fails because the variable is not defined
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.
Move watch filter into storage level
Implement apiserver communication for Vagrant

This implementation is based on the GCE impementation from
618a367dbb48dbaa9c3b50e877858d854322fd0b.
- make cadvisor port configurable on the kubelet.
- added cadvisor port documentation.
Add functions to get kubelet directories.

Gets rid of some magic constants and makes volume plugins (coming later)
cleaner.
Added two test cases for KubeletClient
Add python-cherrypy as explicit install for salt-api
Update roadmap based on discussion at contributor meetup.
Merge pull request #2667 from thockin/klet-dirs

Kubelet directory-name builder funcs
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 --pushup to e2e.go

Silly but hopefully memorable name for an option to --push OR --up
depending on cluster state.
Add util to validate namespaced names
Merge pull request #2795 from zmerlynn/pushup

Add --pushup to e2e.go