The Spacetop AR laptop made a splash when it debuted a few years ago with an intriguing pitch: What if you could have a notebook that works entirely through augmented reality glasses, without a built-in screen of its own? Unfortunately, we found the Spacetop experience to be underwhelming, and the hardware seemed like a tough sell for $1,900. Last Fall, Spacetop's creator Sightful told CNET t [...]