Suppression of warnings

OffsetOf: use of static_cast
Updatable: API and virtual destructor
Drawable: virtual destructor
Vector: std::abs should be "the" abs.
AbstractClass: API
+Updatable: Like for others abstracts
Buffer: nullptr for pointer to function.
Image: wasn't returning a vector.

Former-commit-id: 57e0009286a02b9e3b0b81945e500d7d9e466ae2

include/Nazara/Utility/AbstractAtlas.hpp

@@ -35,7 +35,7 @@ class NAZARA_API NzAbstractAtlas
 
 		void RemoveListener(Listener* font) const;
 
-		class Listener
+		class NAZARA_API Listener
 		{
 			public:
 				Listener() = default;