New node: Morph (#1576)

* Add morph node

* Range slider time parameter, better lerping

* Lerp more fill and stroke parameters

---------

Co-authored-by: Keavon Chambers <keavon@keavon.com>

libraries/bezier-rs/src/subpath/core.rs

@@ -112,7 +112,7 @@ impl<ManipulatorGroupId: crate::Identifier> Subpath<ManipulatorGroupId> {
 		&self.manipulator_groups
 	}
 
-	/// Returns a mutable vec of the [ManipulatorGroup]s in the `Subpath`.
+	/// Returns a mutable reference to the [ManipulatorGroup]s in the `Subpath`.
 	pub fn manipulator_groups_mut(&mut self) -> &mut Vec<ManipulatorGroup<ManipulatorGroupId>> {
 		&mut self.manipulator_groups
 	}

libraries/bezier-rs/src/subpath/structs.rs

@@ -111,6 +111,12 @@ impl<ManipulatorGroupId: crate::Identifier> ManipulatorGroup<ManipulatorGroupId>
 	pub fn is_finite(&self) -> bool {
 		self.anchor.is_finite() && self.in_handle.map_or(true, |handle| handle.is_finite()) && self.out_handle.map_or(true, |handle| handle.is_finite())
 	}
+
+	/// Reverse directions of handles
+	pub fn flip(mut self) -> Self {
+		std::mem::swap(&mut self.in_handle, &mut self.out_handle);
+		self
+	}
 }
 
 #[derive(Copy, Clone)]