add manifest webhooks tests
inlude manifest test file
Merge branch 'master' into test_webhook_manifest
Add tests for the scaling group manifest with webhooks.
Removed merge conflicts.
Removed timing requirement for manifest query
Review changes
Review changes 2
Merge branch 'master' into test_webhook_manifest
Review changes 2
Merge pull request #590 from rackerlabs/test_webhook_manifest

AS-44: Test webhook manifest