fix a typo in fiteach for start_from_point='center'
fix a typo in fiteach for start_from_point='center'

keflavich/pyspeckit,pyspeckit/pyspeckit,e-koch/pyspeckit,jpinedaf/pyspeckit,jpinedaf/pyspeckit,e-koch/pyspeckit,vlas-sokolov/pyspeckit,low-sky/pyspeckit,vlas-sokolov/pyspeckit,keflavich/pyspeckit,pyspeckit/pyspeckit,allisony/pyspeckit,low-sky/pyspeckit,allisony/pyspeckit