More than 300 budding entrepreneurs turn out at a casting call to see who may be bait for the reality show's investors. Head casting producer Scott Salyers greeted the first group of “Shark Tank” hopefuls and went over the ground rules at Wednesday’s open casting call in Portland for the popular ABC reality show. “If part of your pitch is ‘My product speaks for itself,’ you’re probably not going to get on the show,” he said. “We want you to convince us with your words.” Portl