Ok, so everybody who has to file a tax return this year gets a little break, as April 15 falls on Saturday, placing the actual factual deadline on the following Monday, April 17. But for residents of the District (and a few northeastern states) Uncle Sam brings the extra generosity this year. As it turns out, folks that live in D.C., along with those in Maine, Massachusetts, New Hampshire, New York, and Vermont (suck it,…