fixed an unexpected numpy behavior: argmin flattens, argsort doesn't
fixed an unexpected numpy behavior: argmin flattens, argsort doesn't

pyspeckit/pyspeckit,vlas-sokolov/pyspeckit,allisony/pyspeckit,low-sky/pyspeckit,jpinedaf/pyspeckit,bsipocz/pyspeckit,vlas-sokolov/pyspeckit,bsipocz/pyspeckit,mikelum/pyspeckit,e-koch/pyspeckit,keflavich/pyspeckit-obsolete,dinossimpson/pyspeckit,dinossimpson/pyspeckit,keflavich/pyspeckit,allisony/pyspeckit,pyspeckit/pyspeckit,jpinedaf/pyspeckit,e-koch/pyspeckit,low-sky/pyspeckit,mikelum/pyspeckit,keflavich/pyspeckit