Put back old version of OctTree for testing, made unit tests.

Tests shows the old version checks for collisions etc. faster, new version adds objects into tree faster, and doesn't give duplicated results.

src/Engine/Core/OctTree.cpp

@@ -163,7 +163,7 @@ OctTree::OctChild::~OctChild()
 
 void OctTree::Update(float dt, World* world, Camera* cam)
 {
-    for (ComponentWrapper& c : world->GetComponents("Collision")) {
+    for (ComponentWrapper& c : *world->GetComponents("Collision")) {
         AABB aabb;
         aabb.CreateFromCenter(c["BoxCenter"], c["BoxSize"]);
         AddDynamicObject(aabb);