I heard Gabriel Kahane at Joe’s Pub Wednesday night. If Billy Joel and Paul McCartney can write “classical music”, why can’t composers write “pop music”? 1. Gabe Kahane is a good singer, great pianist and out of this world showman. His wry and wonderful wit comes through his music and lyrics. Wednesday night Kahane shared his sounds with humor, humility and always in an entertaining way. 2. Ensemble with the four man band, including: piano, banjo, violin, clarinet, bass clarinet, drums, guitar, electric bass, toy piano and a melodic, was generally tight and toe tapping. Less stellar was the drummer