feat(node): add NodeRef type

src/nodes/spatial.rs

@@ -1,8 +1,6 @@
-use super::core::Node;
+use super::core::{Node, NodeRef};
 use crate::core::client::Client;
 use anyhow::Result;
-use std::cell::RefCell;
-use std::rc::Weak;
 use vek::mat::repr_c::row_major::Mat4;
 
 pub struct Spatial {
@@ -18,7 +16,7 @@ impl<'a> Spatial {
 		client: Option<&'a mut Client<'a>>,
 		path: &str,
 		transform: Mat4<f32>,
-	) -> Result<Weak<RefCell<Node<'a>>>> {
+	) -> Result<NodeRef<'a>> {
 		let node = Node::from_path(client, path)?;
 		node.upgrade().unwrap().borrow_mut().spatial = Some(Spatial::new(transform));
 		Ok(node)