Conservative superstar Sarah Palin opened the door yesterday to joining forces with Mitt Romney for a 2012 White House run - a hot ticket that has some Republicans licking their chops at the prospect of unseating President Obama. “Sounds pretty good,” Palin declared at yesterday’s Tea Party Express rally on the Common when asked about pairing up with the former Bay State governor - giving the idea a big thumbs-up as she left the stage after her headline speech. Last night, as Palin stopped for cannoli at Mike’s Pastry in the North End, she said she was “serious” about the...