Added some reserved fields to BControlLook.

* This makes future changes less troublesome, although we should also add
  some virtual slots there (probably just dozens of it, though, that's why
  I was being lazy).
* Don't pass messages by value; they are copied twice this way.
* Minor coding style corrections, automatic whitespace cleanup.

headers/os/interface/ControlLook.h

@@ -272,7 +272,8 @@ public:
 									const rgb_color& base, uint32 flags,
 									const BPoint& where);
 
-			void				SetBackgroundInfo(BMessage msg);
+			void				SetBackgroundInfo(
+									const BMessage& backgroundInfo);
 
 protected:
 			void				_DrawButtonFrame(BView* view, BRect& rect,
@@ -369,7 +370,8 @@ private:
 			bool				fCachedOutline;
 			int32				fCachedWorkspace;
 			BMessage			fBackgroundInfo;
-		
+
+			uint32				_reserved[20];
 };
 
 extern BControlLook* be_control_look;