Drop unused parameter
Drop unused import
Allow for availability-zone aliases
Stop searching for puppet files once a match is found
Fix validation of scheduled auto-scaling actions
Tweak error messages to fit in the template
Ignore None values in validation and translation

Keys will still be validated, where appropriate, but the value itself
will be ignored.

When merging multiple sources of data, something barely exposed for the
time being, this allows for "deleting" settings that were previously
defined, by setting them to 'null'/None.