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

src/Nazara/Core/Updatable.cpp

@@ -0,0 +1,8 @@
+// Copyright (C) 2015 Jérôme Leclercq
+// This file is part of the "Nazara Engine - Core module"
+// For conditions of distribution and use, see copyright notice in Config.hpp
+
+#include <Nazara/Core/Updatable.hpp>
+#include <Nazara/Core/Debug.hpp>
+
+NzUpdatable::~NzUpdatable() = default;