The Madison Theater, the 88-year-old moviehouse in Albany’s Pine Hills, will close Jan. 1 for a stem-to-stern cleaning and improvements while its owners decide on purchase offers from two potential buyers.“I really can’t be specific, but I have a couple of interesting deals in front of me that would keep the integrity of the theater and be much more responsive to the community,” said Gunther Fishgold, founder and president of Tierra Farm, which owns the Madison and its two abutting businesses.