SceneMainLoop -> SceneTree

-=-=-=-=-=-=-=-=-=-=-=-=-=-

*YOUR SOURCE MIGHT NOT WORK*
For mor information on fix:
https://github.com/okamstudio/godot/wiki/devel_scene_tree

Other stuff:
-Shower of bullets demo
-Fixes all around

modules/gridmap/grid_map.cpp

@@ -677,7 +677,7 @@ void GridMap::_octant_clear_baked(const OctantKey &p_key) {
 	g.bake_instance=RID();
 	g.baked=Ref<Mesh>();
 
-	if (is_inside_scene())
+	if (is_inside_tree())
 		_octant_enter_world(p_key);
 	g.dirty=true;
 	_queue_dirty_map();