punch up luigi and purpdrank with NCBLIT_2x2

src/demo/luigi.c

@@ -157,6 +157,7 @@ int luigi_demo(struct notcurses* nc){
   struct ncvisual_options vopts = {
     .n = notcurses_stddim_yx(nc, &rows, &cols),
     .scaling = NCSCALE_STRETCH,
+    .blitter = NCBLIT_2x2,
   };
   if(ncvisual_render(nc, nv, &vopts) == NULL){
     return -1;

src/demo/view.c

@@ -103,6 +103,7 @@ view_images(struct notcurses* nc, struct ncplane* nstd, int dimy, int dimx){
   }
   free(pic);
   vopts.n = notcurses_stdplane(nc);
+  vopts.blitter = NCBLIT_2x2;
   if(ncvisual_render(nc, ncv, &vopts) == NULL){
     ncvisual_destroy(ncv);
     ncplane_destroy(dsplane);