“I just want to keep putting music out,” Scott Kannberg says with a sense of slacker ease while Skyping from his current home in Mérida, Mexico. “I’m having fun doing it.” It’s been a while since Kannberg—known as Spiral Stairs since co-founding Pavement with fellow singer/ guitarist Stephen Malkmus in 1989—has been so prolific or really even played music on a regular basis….