Kill zombie windows

As described in #52, we have a zombie window problem:

1. Open a survey from a notification
2. Close the survey without submitting a form
3. Open another survey from the notification
4. The old survey that you closed will re-open (!!!)

This adds a hack to re-close all of the zombies as soon as they reopen.
No, I meant if you keep closing them every time you create a window, then there shouldn't be more than one zombie tab at any given time, right? The fact that you are assigning a single element to the array seems to indicate that as well.

As an example:
tab1 opens, becomes zombie.
tab2 opens, kills tab1. itself becomes zombie.
tab3 opens, kills tab2, itself becomes zombie and so on.