Caavo’s $400 set-top box unites Amazon, Apple, and everything else into one TV interface

Video streaming boxes and game consoles tend to create a new problem for every one they solve: for every improved TV interface, there’s another input to switch to, or another remote control to use. And you still can’t get certain content stores, like Amazon’s Video app and Apple’s iTunes, on the same interface.That’s what Caavo is hoping to solve with its new, long-in-the-works media box, a $399, multi-port box that puts all of your streaming video apps into one int