Moves more stuff from windows.h.
- include/winuser.h - interface relevant to user32.spec
- include/wine/winuser16.h - the old 16 bit interface (internal use)
- include/winbase.h - some minor updates to keep things coherent.
- Lot of other files made to include wine/winuser16.h, which is no
  longer included from windows.h

diff --git a/controls/button.c b/controls/button.c
index 7ab8c33..13b5689 100644
--- a/controls/button.c
+++ b/controls/button.c
@@ -7,7 +7,8 @@
 
 #include "win.h"
 #include "button.h"
-#include "windows.h"
+#include "winuser.h"
+#include "wine/winuser16.h"
 #include "tweak.h"
 
 static void PB_Paint( WND *wndPtr, HDC32 hDC, WORD action );