Refactoring of SDL API usage:

- Rect no longer inherits from SDL_Rect
- renamed vcmi functions that used SDL naming format
- moved all functions in SDL_Extensions file into CSDL_Ext namespace
- SDL_Rect is now used only by SDL_Extensions, all other code uses Rect

client/widgets/ObjectLists.h

@@ -12,7 +12,7 @@
 #include "../gui/CIntObject.h"
 
 struct SDL_Surface;
-struct Rect;
+class Rect;
 class CAnimImage;
 class CSlider;
 class CLabel;