What does it say that a Warren Zevon tribute concert Friday night featured more than 30 songs, was performed by well over 50 musicians, and stretched nearly to four hours in the end … and still felt skimpy? It says that some of us are just a little too greedy, 22 years after the honoree’s death, to hear as many of the rock genius’s greatest songs performed as possible, even if that really would entail playing it all night long. Given that no one involved could really wait till they’re dead to