~ Initial SDL2 implementation

Limitation
- Dependent projects need to set NAZARA_PLATFORM_SDL2 if nazara has been build with SDL2 since OpenGL.hpp (and maybe some other headers) exposes platform details
- SDL2 window doesn't supports async window since the API isn't fitting for now
- Contexts parameters can't be changed until we close all the SDL windows (SDL limitation)

src/Nazara/Platform/SDL2/IconImpl.cpp

@@ -0,0 +1,49 @@
+// Copyright (C) 2017 Jérôme Leclercq
+// This file is part of the "Nazara Engine - Platform module"
+// For conditions of distribution and use, see copyright notice in Config.hpp
+
+#include <Nazara/Platform/Debug.hpp>
+#include <Nazara/Platform/SDL2/IconImpl.hpp>
+#include <Nazara/Utility/Image.hpp>
+#include <Nazara/Utility/PixelFormat.hpp>
+
+namespace Nz
+{
+	bool IconImpl::Create(const Image& icon)
+	{
+		m_iconImage = icon;
+		if (!m_iconImage.Convert(PixelFormatType_BGRA8))
+		{
+			NazaraError("Failed to convert icon to BGRA8");
+			return false;
+		}
+
+		m_icon = SDL_CreateRGBSurfaceWithFormatFrom(
+			m_iconImage.GetPixels(),
+			m_iconImage.GetWidth(),
+			m_iconImage.GetHeight(),
+			32,
+			32 * m_iconImage.GetWidth(),
+			SDL_PIXELFORMAT_BGRA8888
+			);
+
+		if (!m_icon)
+		{
+			NazaraError(SDL_GetError());
+			return false;
+		}
+
+		return true;
+	}
+
+	void IconImpl::Destroy()
+	{
+		SDL_FreeSurface(m_icon);
+		m_iconImage.Destroy();
+	}
+
+	SDL_Surface* IconImpl::GetIcon()
+	{
+		return m_icon;
+	}
+}