Iterating an array by a GList is considerably faster than
continuously retrieving items, however it is also a lot
more complicated. So the new macro takes care of that and
uses a new semi-private function to avoid copying the list.
Note that the macro can't be nested, which basically isn't
useful in practise anyway.
The secondary-icon-released signal of the location action returns
a boolean now so a callback can indicate that it handled it. So
if the feed panel is active, it adds feeds to the panel and
suppresses the default action.
A possible crash when disabling the panel and clicking the icon
afterwards is fixed by adding a missing signal disconnection.
