Apple slyly enables background iDisk music streaming in iOS 4 Well, would you look at that? The v1.2 update to MobileMe iDisk that Apple pushed out last month has a secret -- er, did have a secret. One of the concealed new features of the app is background streaming, or as Apple puts it, the ability to "play audio from your iDisk while using another app." For starters, it's pretty fantastic just t