Instances in pop-ups don't unregister http listeners

[shadybones]

State: auto-export on, DBG_NETEXPORT on
Env: Mac FF16,FF28
Issue: Popups start a new instance of FB and NE, and after close, FBTrace still shows prints from closed instance.

Temp Fix (resolves issue for me) :
In automation.js, append in main function:
window.top.addEventListener("close",HttpObserver.unregister.bind(HttpObserver));