MANCHESTER, N.H. (AP) — Mitt Romney and Paul Ryan blasted President Barack Obama’s Medicare plan before New Hampshire voters today, even though a central element of that plan once was embraced by Ryan, the GOP vice presidential candidate. “Medicare should not be a piggy bank for Obamacare,” Ryan told about 3,000 people at an outdoor rally where he joined Romney for the first time in a week. The two men criticized Obama’s plan to reduce Medicare’s projected growth by $716 billion over 10 years. Obama says the savings would come from reduced payments to — and greater efficiency by — …