fix for issue119: inform the user why the fitter can't be loaded
fix for issue119: inform the user why the fitter can't be loaded

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