While Apple has kept the iPad 2 in its lineup, it has surprisingly pulled the third-generation iPad from its online store in the U.S. after today’s announcement of the iPad mini and fourth-generation iPad. The store now shows the iPad mini, iPad 2 and iPad with Retina display — however, the latter is the fourth-generation iPad, essentially replacing the third-generation iPad entirely. For the time being, Apple is selling off refurbished third-generation…