Couple of assertions

src/dawn/scene/Scene.cpp

@@ -35,6 +35,7 @@ void Scene::update() {
 SceneItem * Scene::createSceneItem() {
   sceneitemid_t id = this->nextId++;
   auto item = new SceneItem(this, id);
+  assertNotNull(item);
   this->itemsNotInitialized[id] = item;
   return item;
 }

src/dawn/scene/SceneItem.hpp

@@ -50,6 +50,7 @@ namespace Dawn {
       template<class T>
       T * addComponent() {
         auto component = new T(this);
+        assertNotNull(component);
         this->components.push_back(component);
         return component;
       }

src/dawn/scene/SceneItemComponent.cpp

@@ -11,6 +11,7 @@
 using namespace Dawn;
 
 SceneItemComponent::SceneItemComponent(SceneItem *item) {
+  assertNotNull(item);
   this->item = item;
   this->transform = &item->transform;
 }