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

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

src/screen.h

@@ -0,0 +1,60 @@
+/* vim:expandtab:ts=2 sw=2:
+*/
+/*  Grafx2 - The Ultimate 256-color bitmap paint program
+
+    Copyright 2018 Thomas Bernard
+    Copyright 2008 Yves Rizoud
+    Copyright 2007 Adrien Destugues
+    Copyright 1996-2001 Sunset Design (Guillaume Dorme & Karl Maritaud)
+
+    Grafx2 is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License
+    as published by the Free Software Foundation; version 2
+    of the License.
+
+    Grafx2 is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Grafx2; if not, see <http://www.gnu.org/licenses/>
+*/
+
+//////////////////////////////////////////////////////////////////////////////
+///@file screen.h
+/// Screen update (refresh) system
+//////////////////////////////////////////////////////////////////////////////
+
+#ifndef SCREEN_H_INCLUDED
+#define SCREEN_H_INCLUDED
+
+#include "struct.h"
+#include "global.h"
+
+byte Get_Screen_pixel(int x, int y);
+
+void Set_Screen_pixel(int x, int y, byte value);
+
+byte* Get_Screen_pixel_ptr(int x, int y);
+
+void Screen_FillRect(int x, int y, int w, int h, byte color);
+
+void Update_rect(short x, short y, unsigned short width, unsigned short height);
+void Flush_update(void);
+void Update_status_line(short char_pos, short width);
+
+int SetPalette(const T_Components * colors, int firstcolor, int ncolors);
+
+///
+/// Clears the parts of screen that are outside of the editing area.
+/// There is such area only if the screen mode is not a multiple of the pixel
+/// size, eg: 3x3 pixels in 1024x768 leaves 1 column on the right, 0 rows on bottom.
+void Clear_border(byte color);
+  
+extern volatile int Allow_colorcycling;
+
+/// Activates or desactivates file drag-dropping in program window.
+void Allow_drag_and_drop(int flag);
+
+#endif // SCREEN_H_INCLUDED