Compare base window for icons
Compare base window for icons

The close listener target might refer to some other object in moz2,
hence comparing the dom windows would fail. Using baseWindow
to compare windows fixes this.

Closes GH-3

jeffkowalski/mintrayr,jeffkowalski/mintrayr,jeffkowalski/mintrayr,nmaier/mintrayr,nmaier/mintrayr,nmaier/mintrayr,jeffkowalski/mintrayr,nmaier/mintrayr