Enable public IPs even in not createExternal...

This allows the proxier to portal Public IPs even if the
createExternalLoadBalancer flag is not set.

This also fixes what appears to be a bug in the createExternalLoadBalancer path
wherein multiple PublicIPs would get truncated.
For GCE, allow insecure registries anywhere in 10.0.0.0/8.
Support remote docker hosts on OS X.

This commit brings two main changes, notably:

Two new options that can be set as environment variables

- DOCKER_OPTS: any arbitrary set of docker options. Example: --tlsverify
- DOCKER_NATIVE: This forces the use of the native docker available.
                 This is most useful if you're on OS X and do not want
                 to use boot2docker.

Now uses 'docker cp' instead of tar piping to transfer files. This
currently must be done by copying the binaries off of the docker volume
and into a local filesystem (/tmp) before a docker cp is done. This
workaround will no longer be necessary after bug fix
https://github.com/docker/docker/pull/8509 makes it into stable.

This was necessary because the tar | tar method was creating corrupted
archives on OS X even with the < /dev/null workaround.
Merge pull request #2620 from jbeda/insecure-registry-fix

For GCE, allow insecure registries anywhere in 10.0.0.0/8.
Merge pull request #2692 from jameskyle/develop

Support remote docker hosts on OS X.
Merge pull request #2635 from thockin/public-ip

Enable public IPs even in not createExternal...
Refactor kubelet, standalone k8s and integration test to all use the same code.
Kubernetes version v0.6.0
Kubernetes version v0.6.0-dev
Merge pull request #2698 from brendandburns/release

Release 0.6.0
Merge pull request #2689 from brendandburns/standalone

Refactor kubelet, standalone k8s and integration test to all use the same code.
Update exec health check message logged

Update message logged after performing exec health check per #2708.
Merge pull request #2709 from mindscratch/master

Update exec health check message logged