Use callback attributes to repaint editors

This would not work with the `upm-support` branch #14 as the attributes are not searched for in the attribute that these scripts are in by default.

Author: rogerbarton

scripts/Editor/DllManipulatorEditor.cs

@@ -330,8 +330,6 @@ static string GetFirstAssemblyToList(string[] allAssemblies)
         public static void LoadAllShortcut()
         {
             DllManipulator.LoadAll();
-            RepaintAll();
-            DllManipulatorWindowEditor.RepaintAll();
         }
 
         #if UNITY_2019_1_OR_NEWER
@@ -342,10 +340,10 @@ public static void LoadAllShortcut()
         public static void UnloadAll()
         {
             DllManipulator.UnloadAll();
-            RepaintAll();
-            DllManipulatorWindowEditor.RepaintAll();
         }
 
+        [NativeDllLoadedTrigger]
+        [NativeDllAfterUnloadTrigger]
         public static void RepaintAll()
         {
             var editors = Resources.FindObjectsOfTypeAll<DllManipulatorEditor>();

scripts/Editor/DllManipulatorWindowEditor.cs

@@ -15,6 +15,8 @@ static void Init()
             window.Show();
         }
 
+        [NativeDllLoadedTrigger]
+        [NativeDllAfterUnloadTrigger]
         public static void RepaintAll()
         {
             if(window) window.Repaint();