Buffer::Unmap no longer return boolean

Made no sense: What do you want to do when your buffer doesn't unmap ?
Tt now throw a warning by itself in case of failure


Former-commit-id: f776af16787316bbe1d55686a1db2c2e0f79d210

src/Nazara/Utility/SkeletalMesh.cpp

@@ -314,8 +314,7 @@ void NzSkeletalMesh::Skin(const NzSkeleton* skeleton) const
 		outputVertex++;
 	}
 
-	if (!m_impl->vertexBuffer->Unmap())
-		NazaraWarning("Failed to unmap vertex buffer");
+	m_impl->vertexBuffer->Unmap();
 
 	m_impl->aabb = skeleton->GetAABB();
 }