Null out component when editor is destroyed to minimize leaks

Signed-off-by: Nathan Sobo <nathan@github.com>

src/text-editor.coffee

@@ -478,7 +478,9 @@ class TextEditor extends Model
     @gutterContainer.destroy()
     @emitter.emit 'did-destroy'
     @emitter.clear()
-    @editorElement = null
+    @component?.element.component = null
+    @component = null
+    @lineNumberGutter.element = null
 
   ###
   Section: Event Subscription