Merge branch 'release-1.6.6' into develop

* release-1.6.6:
  Bumping version to 1.6.6
  Update changelog with new service updates
Remove Route53 resource ID customization.

This is now handled by Botocore as of boto/botocore#398.
Merge pull request #1045 from danielgtaylor/route53-customization

Remove Route53 resource ID customization.
Add latest bug fixes to changelog
[EMR] Add a working streaming steps example to add-steps and create-cluster
Add ``opsworks register`` command.

It registers an EC2 instance or machine with AWS OpsWorks
Update requirements and changelog for opsworks
Update changelog with service updates
Bumping version to 1.6.7
Merge branch 'release-1.6.7'

* release-1.6.7:
  Bumping version to 1.6.7
  Update changelog with service updates
  Update requirements and changelog for opsworks
  Add ``opsworks register`` command.
  [EMR] Add a working streaming steps example to add-steps and create-cluster
  Add latest bug fixes to changelog
  Remove Route53 resource ID customization.