app icons and launch images are now managed via asset catalog
remove obsolete icons (were accidentally committed in c47db68)
update launch images
update application icons for iOS 7 (add transparent border)
fix spacing between text and activity indicator in status view
fix memory leak when allocating UIWindow
improve name of "iPhone 4S" demo profile (fixes #210)
running out of stones is not possible (closes #44)

running out of stones is not something that happens in practice
(typically players would exchange prisoners if such a situation arose,
or borrow stones from a neighbour table); most rulesets do not even
have a rule that covers the scenario (one known exception are the
Tromp-Taylor rules where the rules commentary states "Each player has
an arbitrarily large set of stones of his own color")