ST. CLOUD, Minn. (AP) — Minnesotans put Vice President Joe Biden and four Cabinet members on the spot Thursday, asking how federal aid could help their transit projects, community colleges and small businesses make it through the economic downturn.  The focus of the town-hall-style forum in a bus garage in central Minnesota was the middle class, and Biden told the crowd of more than 400 that the Obama administration is making sure the $787 billion economic stimulus package helps middle-class families get through the downturn and prosper when the economy eventually turns around. “We’ll measure our success in these four or eight years based on one thing: whether or not we’ve been able to raise the standard of living for middle-class people,” Biden said.