Two months ago, Andrew Chalila was sleeping on the floor at the Hope House, a Bangor homeless shelter, with 16 other men, not all of whom were as committed to staying sober as the 28-year-old is. Today, Chalila has his own room at the Fresh Start Sober Living House in Bangor that he shares with his Siamese cat, Daisy Buchanan. “Words can’t describe what this house means to me,” Chalila said Tuesday at an open house for local media.