fix(aws): error with other instances without tags

while starting the cluster, and having already other non-kubernetes
instances active without tags, an KeyError throwed.
enhancement(aws): checks for existing kubernetes vpc first

without this check, kube-up creates a new vpc every time. Now it will
reuse the vpc tagged Kubernetes.
enhancement(aws): using iam role to pass aws credentials
enhancement(aws): added logging variable and more verbose output
fix(aws): fix with non us standard region
fix(aws): cloud provider wasn't set, corrected cloud config syntax
docs: CoreOS worker nodes should not require a local etcd install
Merge pull request #2642 from kelseyhightower/update-to-0.5

docs: CoreOS worker nodes should not require a local etcd install
Update Godeps with latest goamz & add elb
WIP on support for ELB
Merge branch 'master' of github.com:justinsb/kubernetes
Merge branch 'aws_elb'
Initial kube-push for AWS
Merge remote-tracking branch 'dutchcoders/master'

Conflicts:
	cluster/aws/config-default.sh
Make kube-down AWS cleanup (more) idempotent
More idempotency for kube-down
Set cloud_provider / cloud_config for aws in kube-apiserver
Remove extra spaces from cloud_ args
Fix syntax of /etc/aws.conf

Delimiter is =, not :
Add note that Region can be easily determined