By Julia Burke, Beer Editor Three Heads Brewing is on a roll lately with new releases, and Bromigo, their very first fall seasonal offering, is an interesting foray into flavorings: it's a smoked maple amber brewed with maple syrup. The nose is wonderfully complex for a fall seasonal — sweet and smokey, with full and thick maple notes backed up by toffee and vanilla and a firm roast. There's no aggressive alcohol to speak of, just the rich scents of a woodsy fall flannel-wearing, maple-syrup-tapping party.  Bready malts and roast dominate the palate. It's not a thick beer, for the lushness of…