Tesla shares jumped more than 4 percent Monday after Elon Musk revealed a new, $78,000, souped-up version of the electric-car maker’s mass-market Model 3 sedan. The fully-loaded Model 3 will go from zero to 60 mph in 3.5 seconds — more than a half-second sooner than the basic, $35,000 Model 3, Musk announced Sunday on...