travis - added tkinter install
travis - added tkinter install

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