Trying a possible fix for gmail's URL redirection

The fix stores a 'url' field in each account object at the time the background
page initializes. It obtains the redirected url using a <meta> tag in gmail's
response. The gmail.getAccountUrl method always returns this url value instead.
Seems to work for now. Might have to run the updateAccountUrl method more often
than just the initialization, in case it fails during init.
Simplified parsing and fixed a bug in util.each