Add set quality comparison to ignore filter

[seanmil]

Overview

This pull request introduces new functionality to the --ignore option, allowing array values to parameters to be ignored if they have set equality.

Resources may accept array parameters but may not change behavior depending on the order of those parameters. In those situations it would be good to be able to ignore changes due only to array ordering.

Checklist

• Make sure that all of the tests pass, and fix any that don't. Just run rake in your checkout directory, or review the CI job triggered whenever you push to a pull request.
• Make sure that there is 100% test coverage by running rake coverage:spec or ignoring untestable sections of code with # :nocov comments. If you need help getting to 100% coverage please ask; however, don't just submit code with no tests.
• If you have added a new command line option, we would greatly appreciate a corresponding integration test that exercises it from start to finish. This is optional but recommended.
• If you have added any new gem dependencies, make sure those gems are licensed under the MIT or Apache 2.0 license. We cannot add any dependencies on gems licensed under GPL.
• If you have added any new gem dependencies, make sure you've checked in a copy of the .gem file into the vendor/cache directory.

[ahayworth]

Looks good to me! 😄