Fix some warnings

engine/world/SceneGraph.cpp

@@ -109,6 +109,7 @@ int32_t SceneGraph::node(StringId32 name) const
 	}
 
 	CE_FATAL("Node not found");
+	return 0;
 }
 
 //-----------------------------------------------------------------------------

engine/world/Unit.cpp

@@ -219,7 +219,7 @@ void Unit::create_physics_objects()
 			Actor* a1 = actor_by_index(joint.actor_0);
 			Actor* a2 = actor_by_index(joint.actor_1);
 
-			JointId id = m_world.physics_world()->create_joint(pr, i, *a1, *a2);
+			m_world.physics_world()->create_joint(pr, i, *a1, *a2);
 		}
 	}
 }

engine/world/World.cpp

@@ -342,7 +342,7 @@ void World::process_physics_events()
 			}
 			case physics_world::EventType::TRIGGER:
 			{
-				physics_world::TriggerEvent trigg_ev = *(physics_world::TriggerEvent*) event;
+				// physics_world::TriggerEvent trigg_ev = *(physics_world::TriggerEvent*) event;
 
 				// Log::d("type    = %s", trigg_ev.type == physics_world::TriggerEvent::BEGIN_TOUCH ? "begin" : "end");
 				// Log::d("trigger = (%p)", trigg_ev.trigger);