SCHENCTADY - Joe Biden walked out on stage at Proctors on Monday evening to a standing ovation and a chorus of "Happy Birthday."It was not a tough crowd: A near-capacity audience of more than 2,200 showed up to hear Biden, who turned 75 Monday, talk about his new memoir, "Promise Me, Dad: A Year of Hope, Hardship, and Purpose." But it was clear that the overwhelmingly Democratic attendees were, at least for an evening, soaking up the presence of a political figure unlikely to pick a Twitter fight.