make docker-push work with docker-tag artifacts

website: Add all boot commands from source to docs.

website: Minor edits

website: Update chef-solo.html.markdown

website: Update amazon.html.markdown

post-processor/parallels: Removed unnecessary filling the Vagranfile

website: ec2:ModifyImageAttribute already included in the sample policy

providers/aws: Ignore transient network errors when fetching AWS state.

website: Update example to match parameter.

provisioner/ansible: Colorize Ansible output, and don't buffer output.

provisioner/shell: single quote env var values.

Setting environment variables for the ansible-playbook invocation.

ANSIBLE_FORCE_COLOR will ensure output is colorized.  PYTHONUNBUFFERED will stream output as Ansible runs, vs getting a big dump of output at the end.

The example showed "path" instead of "output".

Given that state fetching is an idempotent operation, a transient
network error should not cause the entire build to fail. Instead,
retry when such errors are encountered.

fix a minor typo in platforms.html

fix: Respect metadata supplied for GCE builders.

Fixed dead links in doc section environment-variables.

Use middleman-hashicorp

Previously, any per instance metadata supplied via the GCE builder
was ignored.

Test plan:

- make test
- Manual testing via:
-- Created a packer config that contained a GCE builder with custom
   metadata set.
-- Ran `packer build`.
-- Verified the instance had the correct metadata in the GCE console.

ec2:ModifyImageAttribute is already included in the sample policy JSON (line 67 in the source file), so the comment about optionally adding it only adds confusion.

builder/parallels: Create VM without hdd and then add it later

builder/parallels: Rely on Cleanup functions to detach devices