Add knife params support to EC2 controller provisioner
Merge pull request #559 from espnbr/feature/add-knife-params-support-to-ec2

Add knife params support to EC2 controller provisioner
Updated container submodules and cookbook SHA.
Updated docker tags in image prep scripts.
Removed docker tags now that we're back to trusted builds.
Merge pull request #566 from opdemand/remove-docker-tags

Removed docker tags now that we're back to trusted builds.
Allow controller to run behind an SSL termination proxy
Updated EC2 AMIs for v0.5.1, fixes #567.
Merge pull request #571 from opdemand/567-time-to-make-the-amis

Updated EC2 AMIs for v0.5.1, fixes #567.
Merge pull request #570 from jwilder/jw-ec2-ssl

Allow controller to run behind an SSL termination proxy
Added comment about HTTPS proxy setting.
Updated Sphinx to v1.2.2.
Updated release procedure doc for upcoming v0.5.1.
removed provision-controller.sh

`vagrant up` already brings up the controller for us, so this file
is no longer required.
Merge pull request #572 from opdemand/update-releases-doc

Update releases doc
Merge pull request #574 from opdemand/remove-provision-script

removed provision-controller.sh
Added missing DigitalOcean cloud regions.
Always use :latest tag for Deis docker images.
Added :latest tag to slugrunner image pulls.
Merge pull request #576 from opdemand/docker-tag-latest

Always use :latest tag for Deis docker images.