Remove unnecessary StackOverlay import

The better name clickOverlays should be accessed from eg. `space.monitor` now.

navigator.js

@@ -11,7 +11,6 @@ const Clutter = imports.gi.Clutter;
 const Tweener = imports.ui.tweener;
 
 var TopBar = Extension.imports.topbar;
-var StackOverlay = Extension.imports.stackoverlay;
 var Scratch = Extension.imports.scratch;
 const Minimap = Extension.imports.minimap;
 const Tiling = Extension.imports.tiling;

scratch.js

@@ -2,7 +2,6 @@ const Extension = imports.misc.extensionUtils.extensions['paperwm@hedning:matrix
 const Meta = imports.gi.Meta;
 
 const TopBar = Extension.imports.topbar;
-const StackOverlay = Extension.imports.stackoverlay;
 const utils = Extension.imports.utils;
 const debug = utils.debug;
 let float;
@@ -13,8 +12,6 @@ function makeScratch(metaWindow) {
     metaWindow.stick();
     metaWindow.clone.hide();
     metaWindow.get_compositor_private().show();
-
-    // StackOverlay.reset();
 }
 
 function unmakeScratch(metaWindow) {
@@ -63,7 +60,6 @@ function show() {
             meta_window.get_compositor_private().show();
     });
     windows[0].activate(global.get_current_time());
-    // StackOverlay.reset();
 }
 
 function hide() {