Allen Johnston | The Music Specialist | www.asha.com   The blueprint for a successful music career has been completely torn up and redrawn. The golden-age formula—record a song, get radio play, sell CDs in stores, tour, and reap the rewards—has fundamentally dried up. The industry we know today is a different beast, shaped by a series of technological and cultural revolutions.   Having witnessed these shifts firsthand, I see them as chapters in an ongoing story. Here’s a look