A letter for Signor Viola   It’s the spring of 1983. Dino Viola, the then president of Roma, is at the office. He’s sat behind his desk about to start work for the day when his personal secretary enters with the morning post. Among the bundle of letters, there is one stamped and mailed from Turin. As he picks up the envelope, studying it carefully before opening the lip, Viola knows exactly from whom it was sent.   Intuition tells him that it’s from the president of Juventus, Giampiero Boniperti. Over the years, the pair had frequently corresponded, writing rather amusing open letters to each other in their respective local papers. They formed part of the build up to matches between their two clubs.…