More Cppcheck fixes

Former-commit-id: 62ab1caa04543da1a169812bb92a450d44f3aec1

src/Nazara/Utility/Algorithm.cpp

@@ -638,7 +638,7 @@ NzBoxf NzComputeAABB(NzSparsePtr<const NzVector3f> positionPtr, unsigned int ver
 	if (vertexCount > 0)
 	{
 		aabb.Set(positionPtr->x, positionPtr->y, positionPtr->z, 0.f, 0.f, 0.f);
-		positionPtr++;
+		--positionPtr;
 
 		for (unsigned int i = 1; i < vertexCount; ++i)
 			aabb.ExtendTo(*positionPtr++);

src/Nazara/Utility/Skeleton.cpp

@@ -333,6 +333,9 @@ bool NzSkeleton::IsValid() const
 
 NzSkeleton& NzSkeleton::operator=(const NzSkeleton& skeleton)
 {
+	if (this == &skeleton)
+		return *this;
+
 	Destroy();
 
 	if (skeleton.m_impl)