Martha A. Mills had grown accustomed to having bricks thrown through her office window, but finding a smoldering bag of dynamite on her chair at her office in downstate Cairo struck a particular nerve.“One time they shot into the office and it hit the Xerox machine and tore a gaping hole into it,” she said. “It still worked, so we let Xerox know that their wounded Xerox machine still worked and we would like for them to fix it when they had a chance.”After work as a civil rights advocate in the …