Delmark Records was founded in 1953 and claims to be the oldest independent record label in the country. Owner Bob Koester also owns and operates what he claims to be the biggest jazz and blues record store in the country, The Jazz Record Mart, also in Chicago. Mr. Koester’s claims are, of course, quiet probably true. The jazz catalog includes everything from straight-ahead to traditional to avant-garde. The AACM (Anthony Braxton, Roscoe Mitchell, Joseph Jarman, Muhal Richards Abrams, et. al.) m …