refactored moments docs
refactored moments docs

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