“Austin City Limits” has long wanted to kick open its doors to hip-hop, but the reckless messages embraced by some rappers made the program’s producers hesitant. But Saturday, for the first time ever, the long-running PBS music showcase will devote its entire hour-long episode to two of hip-hop’s most talented acts: Brooklyn’s Mos Def and … Continue reading 'Austin City Limits' to air first-ever hip-hop hour