Update to latest Godot

voxel.cpp

@@ -166,7 +166,7 @@ void Voxel::set_library(Ref<VoxelLibrary> lib) {
 VoxelLibrary *Voxel::get_library() const {
 	Object *v = _library.get_ref();
 	if (v)
-		return v->cast_to<VoxelLibrary>();
+		return Object::cast_to<VoxelLibrary>(v);
 	return NULL;
 }
 

voxel_terrain.cpp

@@ -122,7 +122,7 @@ Spatial *VoxelTerrain::get_viewer(NodePath path) const {
 	Node *node = get_node(path);
 	if (node == NULL)
 		return NULL;
-	return node->cast_to<Spatial>();
+	return Object::cast_to<Spatial>(node);
 }
 
 void VoxelTerrain::set_material(int id, Ref<Material> material) {