For many people, Evernote has become an essential tool—a smart app with a great ecosystem that just makes sense. The company has started to branch out, moving into the accessories market with items such as last year’s Moleskine notebook, and its new collaboration with Post-it Notes. Now add to that list Côte&Ciel’s Diver Sleeve for Evernote. Where does a MacBook sleeve fit in to the equation? It frankly doesn’t. But it…