[feature] add default layout width control

src/index.html

@@ -150,6 +150,9 @@
                   <div class="control-layout-width-count form-group-text form-group-medium form-group-radius-left"></div>
                 </div>
               </div>
+              <div class="button-wrap">
+                <button class="control-layout-width-default button mb-0" tabindex="1">Default Width</button>
+              </div>
               <hr>
               <label class="control-layout-alignment-label">Area alignment</label>
               <div class="form-grid-wrap">

src/js/control.js

@@ -139,6 +139,23 @@ var control = (function() {
       layout.render.width();
       render.range.count(this);
     }
+  }, {
+    element: helper.e(".control-layout-width-default"),
+    type: "button",
+    additionalEvents: [{
+      event: "click",
+      func: function() {
+        edge.box.open({
+          element: helper.e(".layout"),
+          delay: 500
+        });
+      }
+    }],
+    func: function() {
+      mod.setValue("layout.width", 80);
+      layout.render.width();
+      render.update();
+    }
   }, {
     element: helper.e(".control-layout-alignment-topleft"),
     path: "layout.alignment",