add a wishlist test: slices should slice headers too
add a wishlist test: slices should slice headers too

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