Add destroy method to CodeManager module

src/code_manager/index.js

@@ -219,6 +219,12 @@ export default () => {
       for (var id in defViewers) this.addViewer(id, defViewers[id]);
 
       return this;
+    },
+
+    destroy() {
+      [c, generators, defGenerators, viewers, defViewers].forEach(
+        i => (i = {})
+      );
     }
   };
 };

src/editor/model/Editor.js

@@ -760,7 +760,8 @@ export default Backbone.Model.extend({
       RichTextEditor,
       LayerManager,
       AssetManager,
-      BlockManager
+      BlockManager,
+      CodeManager
     } = this.attributes;
     this.stopDefault();
     DomComponents.clear();
@@ -773,6 +774,7 @@ export default Backbone.Model.extend({
     LayerManager.destroy();
     AssetManager.destroy();
     BlockManager.destroy();
+    CodeManager.destroy();
     this.view.remove();
     this.stopListening();
     this.clear({ silent: true });