Looks like no kids in Boston are doing their homework tonight. Mayor Thomas Menino canceled classes in all public schools for Friday, one day ahead of a massive snowstorm that could deliver up to two feet of snow in the region. Menino also asked all residents to stay off the roads as of noon Friday. New England is expected to be slammed with a “potentially historic” blizzard, which is forecast to start out as a few flakes early Friday morning but then expected to start falling at a rate of about one to two inches per hour between 6 and 7 p.m.