Three weeks after the last beta release, and just a few days after Apple's developer center finished receiving a massive security overhaul, iOS 7 beta 4 is now available to download. The update to Cupertino's upcoming iOS release -- the biggest since the debut of the original SDK -- is heading out over the airwaves now, with a list of fixes and improvements far too long for us to reprint here. Of course, if you're a registered developer,
