For 15 years the small and slightly-worn down Revolution Cafe known affectionately as “The Rev” or “Revolution” was a place where maestros — from the homeless to the well-to-do — went to find community, to share a pitcher of sangria, to meet their life-long loves, and most importantly, to listen to and to play great music. But in March, it closed for good — and not because of an owner unwilling to pay an increased rent.