People get antsy, if not downright angry, when they can’t easily categorize an artist. Gilbere Forte’ has those people close to crawling out of their skins. The Philadelphia-based rapper (singer, songwriter, producer) realizes this, devoting a post on his blog to the questions surrounding him. “Who am I? Where did I come from? What lane is he trying to be in?” he writes. Early last year, he dropped the single “Black Chukkas,” an unsettlingly off-kilter record that sounds like the…