(svn r10121) -Codechange: split renderer from rest of code; no longer any code directly accesses the video-buffer

-Add: added NULL blitter and renderer, which are always used for -vnull
-Add: dedicated driver doesn't blit nor render by default. Can be overruled by user. (-D -b 8bpp-optimized)
-Remove: removed CTRL+D from win32, which is incompatible with above
-Add: extended screenshot support for PNG and BMP
-Codechange: remove all hardcoded 8bpp references and replace them with more dynamic ones
-Codechange: minor stuff in blitters

src/gfx.h

@@ -7,6 +7,7 @@
 
 #include "openttd.h"
 #include "zoom.hpp"
+#include "renderer/renderer.hpp"
 
 enum WindowKeyCodes {
 	WKC_SHIFT = 0x8000,
@@ -93,7 +94,6 @@ void GameLoop();
 void CreateConsole();
 
 typedef int32 CursorID;
-typedef byte Pixel;
 
 struct Point {
 	int x,y;
@@ -134,10 +134,11 @@ struct CursorVars {
 };
 
 struct DrawPixelInfo {
-	Pixel *dst_ptr;
+	void *dst_ptr;
 	int left, top, width, height;
 	int pitch;
 	ZoomLevel zoom;
+	Renderer *renderer;
 };
 
 struct Colour {