Senator Scott Brown switched a key vote from yesterday and joined 57 Democrats and two Republicans this afternoon in advancing a massive financial regulation overhaul. The Massachusetts Republican said that over the last 24 hours he received assurances – from the chief negotiators in the House and Senate, Senator Christopher J. Dodd, and Representative Barney Frank -- that changes he was seeking would be addressed. Those assurances came during a phone call with Frank last night, while the Newton Democrat was working out in the House members gym. Brown was further convinced during a 40-mile bike ride he went on...