将Spline移出Plugin，以调整SplineRenderer的OnWillCameraRender

Assets/Dreamteck/Splines/Components/ISampleModifier.cs

@@ -0,0 +1,11 @@
+using UnityEngine;
+
+namespace Dreamteck.Splines
+{
+    public interface ISampleModifier
+    {
+        public void ApplySampleModifiers(ref SplineSample sample);
+
+        public Vector3 GetModifiedSamplePosition(ref SplineSample sample);
+    }
+}