use screen.h instead of sdlscreen.h, etc.

Create grafx2-win32 MSVC++ project
create keycode.h
various fixes

src/misc.h

@@ -27,6 +27,9 @@
 #ifndef MISC_H__
 #define MISC_H__
 
+/* For sprintf() used in Num2str() and Dec2str(a,b,c) */
+#include <stdio.h>
+
 #include "struct.h"
 #include "global.h"