Rename meta_window_get_outer_rect() to meta_window_get_frame_rect()

For clarity, rename meta_window_get_outer_rect() to match terminology
we use elsewhere. The old function is left as a deprecated
compatibility wrapper.

src/core/stack.c

@@ -1693,7 +1693,7 @@ window_contains_point (MetaWindow *window,
 {
   MetaRectangle rect;
 
-  meta_window_get_outer_rect (window, &rect);
+  meta_window_get_frame_rect (window, &rect);
 
   return POINT_IN_RECT (root_x, root_y, rect);
 }