Separate NAZARA_API into multiple defines (one per module)

To fix inter-module dependency


Former-commit-id: 64704f020e0af22e529d38527323ba977187d4d0

include/Nazara/Utility/Icon.hpp

@@ -9,11 +9,12 @@
 
 #include <Nazara/Prerequesites.hpp>
 #include <Nazara/Math/Vector2.hpp>
+#include <Nazara/Utility/Config.hpp>
 
 class NzImage;
 class NzIconImpl;
 
-class NAZARA_API NzIcon
+class NAZARA_UTILITY_API NzIcon
 {
 	friend class NzWindowImpl;