Change App to be a Seq instead of a Set
Autoscaling tasks can now filter on stack and app tags
Add some more tests for new stack/app features
Check for a healthy elastic search cluster before deploying
Fix up to use the correct name during deployment.

The legacy mechanism used the package name instead of the legacy app name (defaults to the same, but can be overriden - as frontend have done).

This passes in the package so that the original name can be used and also tries to make the code in the ASG filter a little cleaner.
Merge pull request #152 from guardian/sh-autoscaling-stack-app

Stack and App support for Autoscaling deploy types