According to witnesses, 17-year-old Jessica Williams got a powerful punch in the mouth after mouthing off to NYPD housing cop Desmond Nichols last Sunday outside the Tompkins Houses in Bed-Stuy. The trouble started when Nichols stopped Williams for riding her bike on the sidewalk and asked to see her I.D. When pressed for her apartment number, she reportedly dismissed Nichols as a "rookie." This struck a nerve with Nichols (who is, in fact, a rookie),......