Replace public MetaFrameGeometry with MetaFrameBorders

There were actually *two* MetaFrameGeometry structs: one in theme-private.h,
one in frame.h. The latter public struct was populated by a mix of (void*)
casting and int pointers, usually pulling directly from the data in the private
struct.

Remove the public struct, replace it with MetaFrameBorders and scrap all
the pointer hacks to populate it, instead relying on both structs being used
in common code.

This commit should be relatively straightforward, and it should not do any
tricky logic at all, just a sophisticated find and replace.

https://bugzilla.gnome.org/show_bug.cgi?id=644930

src/core/frame.h

@@ -26,17 +26,6 @@
 
 #include "window-private.h"
 
-typedef struct _MetaFrameGeometry MetaFrameGeometry;
-
-struct _MetaFrameGeometry
-{  
-  /* border sizes (space between frame and child) */
-  int left_width;
-  int right_width;
-  int top_height;
-  int bottom_height;
-};
-
 struct _MetaFrame
 {
   /* window we frame */
@@ -71,8 +60,9 @@ MetaFrameFlags meta_frame_get_flags   (MetaFrame *frame);
 Window         meta_frame_get_xwindow (MetaFrame *frame);
 
 /* These should ONLY be called from meta_window_move_resize_internal */
-void meta_frame_calc_geometry      (MetaFrame         *frame,
-                                    MetaFrameGeometry *geomp);
+void meta_frame_calc_borders      (MetaFrame        *frame,
+                                   MetaFrameBorders *borders);
+
 gboolean meta_frame_sync_to_window (MetaFrame         *frame,
                                     int                gravity,
                                     gboolean           need_move,