Apple CEO Tim Cook sent a year-end email to employees that reflects on Apple’s 2013, and alludes to “big plans” in 2014. “We have a lot to look forward to in 2014, including some big plans that we think customers are going to love,” Cook wrote. The email touched on a number of Apple releases and accomplishments in the past year, including iPhone 5s, iOS 7, iPad Air, and the iPad mini with Retina display. It’s notable…