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.
- 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.
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
Merge pull request #2653 from justinsb/default_cluster_monitoring

Default ENABLE_CLUSTER_MONITORING to false
Merge pull request #2652 from justinsb/default_vpc_has_no_tags

Don't assume every AWS VPC has tags
Expand e2e instructions.
Improve error reporting

Follow-up of changes introduced in commit 72c922668fefc1cf671d9c9e38ebf22a22a80dcf
Fix conditional on grains.docker_opts in docker-defaults
Merge pull request #2801 from VojtechVitek/checkError

Improve error reporting
Fix e2e.
Merge pull request #2802 from brendandburns/fix

Fix e2e.
Merge pull request #2779 from thockin/qualname

Add util to validate namespaced names
Add stack of previous values to converter