To Bo Porter, intensity is a light switch. If the Astros never flip the switch on, the young rebuilding club will never stand a chance in 2013. And if the Astros wait until midway through the regular season to see if their light even burns? “You can walk into the room and then you hit the switch and the bulb (can) be blown,” Porter said. So Porter’s flipped the switch himself. The Astros’ new energy began last October, when he officially took over the worst team in baseball two years running. The buzz has been felt since his club’s spring training started last week in Kissimmee, Fla. And with the Astros’ 8-3 victory over the Philadelphia Phillies on Saturday at Bright House Field in both squads’ Grapefruit League opener, Porter proved he’ll do everything he can to keep his team’s switch flipped on as long as he’s calling the shots. A widely derided club many expect to pile up at least 100 losses for the third consecutive season played like a National League squad in the American League, collecting four stolen bases, starting with Justin Maxwell’s first-inning swipe.