Changes to wxWidgets/SDL2 port :

- Updated UI
- OpenGL 3.0 with GLSL/GLSLP-support
- Improvements to Windows version
- Minor changes/bugfixes
Patch from bit.

src/wx-sdl2.h

@@ -5,6 +5,7 @@ extern "C" {
 void leave_fullscreen();
 int getfile(void* hwnd, char *f, char *fn);
 int getsfile(void* hwnd, char *f, char *fn, char *dir, char *ext);
+void screenshot_taken(unsigned char* rgb, int width, int height);
 
 #ifdef __cplusplus
 }
@@ -14,3 +15,4 @@ extern char openfilestring[260];
 
 extern int pause;
 
+extern int take_screenshot;