Just down the street in the South Side Flats from St. Casimir is another church finding new life as condos. Matthew’s Lofts (www.matthewsloftspgh.com) is in the former St. Matthew Catholic Church at 156 S. 19th St., South Side. Built in 1905, the church primarily served the Slovak immigrant community. The Pittsburgh Diocese decommissioned the church in 1992, and…