Results 2 issues of Beth

https://github.com/imgly/rembrandt/blob/1c75f37a3ef19c96e742c548a9223f03965b6eae/lib/image-comparator.js#L94 This should be comparing imageA and imageB but it references imageB twice.

**Is your feature request related to a problem? Please describe.** I'm using a modal to present a form to the user. Accidentally clicking off the form will make it disappear...