efl_gfx_shape: Stroke color use a premultiplied color.

efl_gfx_shape: Stroke color use a premultiplied color.

R, G, and B must not be higher than alpha.

TEST PLAN:
//test code
Ecore_Evas *ee = ecore_evas_new(NULL, 0, 0, 600, 600, NULL);
ecore_evas_show(ee);

Evas *evas = ecore_evas_get(ee);
Evas_Object *vg,*bg;

bg = evas_object_rectangle_add(evas);
evas_object_color_set(bg, 0, 0, 255, 255);
evas_object_focus_set(bg, 1);
evas_object_show(bg);
int w, h;
ecore_evas_geometry_get(ee, NULL, NULL, &w, &h);
evas_object_resize(bg, w, h);

vg = evas_object_vg_add(evas);
evas_object_focus_set(vg, 1);
evas_object_show(vg);
evas_object_resize(vg, w, h);

Efl_VG *shape, *container;
container = evas_vg_container_add(vg);
shape = evas_vg_shape_add(container);

evas_vg_shape_append_rect(shape, 0, 0, 200 , 200, 10, 10);
evas_vg_shape_stroke_color_set(shape, 255, 255, 255, 10);
evas_vg_shape_stroke_width_set(shape, 20);
evas_vg_node_origin_set(shape, 200, 200);

evas_object_vg_root_node_set(vg, container);
ecore_main_loop_begin();
ecore_evas_shutdown();

Change-Id: I7b0b658566b576ca3e5a8e91f20f692381fb3e92