SAN FRANCISCO — Tesla had hoped to lure buyers into its showrooms for S-E-X. The electric automaker's new entry-level sedan, called the Model 3, was supposed to join its upscale cousins the Model S and Model X as the Model E, CEO Elon Musk tweeted Friday. But it's clear Musk still thinks the locker-room joke will land. "Model 3 was going to be called Model E, for obvious dumb humor reasons, but Fo