With another deadline on Monday for Puerto Rico to repay $60 million to bond holders, we take a look at the economic challenges for the commonwealth as tourism dips. Plus, we’ll talk about Wall Streets’ workout — two major fitness companies are planning IPOs. And a Nashville instrument maker has spent millions of dollars over the course of a decade trying to perfect the self-tuning guitar. But this year, Gibson started making automatic tuners a standard feature on most of its electric guitars.