From Punk's Avant Garde To Mainstream Pop-Stardom, Johnathan Richman Remain, Well, Sort Of A Mystery. By Brendan Doherty JONATHAN RICHMAN WILL never grow old, it seems. Nevertheless, there are signs that the perennially young, insanely energetic rocker is succumbing to time. Flecks of gray have broken through Richman's mop of black hair, and those expressive eyes have the beginnings of crow's feet at their corners. His voice, however, remains the untouched sound of the boy at heart. Don't grow up. Always have fun. Seize the day. After 26 years in the business and two dozen albums, 48-y...