Separate NAZARA_API into multiple defines (one per module)

To fix inter-module dependency


Former-commit-id: 64704f020e0af22e529d38527323ba977187d4d0

include/Nazara/Core/Stream.hpp

@@ -11,7 +11,7 @@
 #include <Nazara/Core/Enums.hpp>
 #include <Nazara/Core/String.hpp>
 
-class NAZARA_API NzStream
+class NAZARA_CORE_API NzStream
 {
 	public:
 		NzStream() = default;