Considered one of the best emcees of his (or any) generation, Lupe Fiasco’s sword remains sharp. On his latest the mid-tempo, jazz-infused “No. 1 Headband,” a single from a new full length Samurai (out now on 1st & 15th Too by way of Thirty Tigers), the Chicago rapper slices and dices. Showing off his agility with a dynamically diverse delivery, …