Added serialization attr for default stuff and some constructor helpe…

…rs when creating nodes (#134)

src/draw/default_edge.rs

@@ -10,6 +10,7 @@ use crate::{draw::DrawContext, elements::EdgeProps, DisplayNode, Node};
 
 use super::DisplayEdge;
 
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 #[derive(Clone, Debug)]
 pub struct DefaultEdgeShape {
     pub order: usize,

src/draw/default_node.rs

@@ -11,6 +11,7 @@ use super::DisplayNode;
 /// This is the default node shape which is used to display nodes in the graph.
 ///
 /// You can use this implementation as an example for implementing your own custom node shapes.
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 #[derive(Clone, Debug)]
 pub struct DefaultNodeShape {
     pub pos: Pos2,

src/elements/node.rs

@@ -159,4 +159,9 @@ where
     pub fn set_label(&mut self, label: String) {
         self.props.label = label
     }
+
+    pub fn with_label(mut self, label: String) -> Self {
+        self.props.label = label;
+        self
+    }
 }