Route53 Record.set_alias was broken by the addition of target
health evaluation.  Fix this and add tests for the new usage
and original usage.  Include health evaluation status in to_print.
Fix route53 alias to_print and change default health eval to False
Merge pull request #2126 from jimbrowne/route53-alias-healthcheck-fix

Fix Route53 aliases, which were broken by the addition of health checks. Fixes #2162.