After taking multiple stumbles backwards over the past year-and-change, Chipotle Mexican Grill, Inc. (NYSE: CMG) looks like it may have taken a tentative step forward. The company reported its fourth-quarter results on February 2. While there was some bad news — same-store sales were down 4.8% and profits fell sharply from the year-ago quarter — there was also a strong indication that the burrito seller’s worst days are behind it, with comps turning positive in December and staying strong in January.