Fresh from his battle with Gap founder Donald Fisher, San Francisco Board of Supervisors President Aaron Peskin is embroiled in two more clashes - one over allegations that he tried to arm-twist city department leaders to do his bidding and another with a supervisor who accuses him of flipping on a vote as a political payback. Supervisor Michela Alioto-Pier's beef is that Peskin switched his vote from "yes" to "no" at an Oct. 23 meeting of the board, and thus effectively tabled a charter amendment she had proposed to set qualifications for appointees to the city's Ethics, Elections and Sunshine...