Back in April, I biked home along the same route I walked so many times during the winter, when the T was out of commission (or, more often, too messed up to be of any real service). During the dark days of winter, Beacon Street was one big mass of white; snowbanks stood shoulder-high in some places, and some spots were so minimally shoveled that I practically had to climb to cross the street. In the spring, the Back Bay streets still glowed white, but this time, it was because of the pale, fluffy blossoms covering all the trees, as…