Unlike model-specific keyboard cases or keyboard covers, Keys-to-Go is one of several Logitech keyboards to embrace the reality that new iPads may vary considerably in size from year to year and screen to screen. Billed as “for iPad” on its packaging, it’s device-agnostic in the sense that it can be Bluetooth paired to any iPad, iPhone, or iPod touch, and will work properly, but the footprint is clearly ideal for Apple’s tablets:…