Fix - Error on hide when popover is not shown

package.json

 {
   "name": "driver.js",
-  "version": "0.9.3",
+  "version": "0.9.4",
   "description": "A light-weight, no-dependency, vanilla JavaScript library to drive the user's focus across the page",
   "main": "dist/driver.min.js",
   "types": "types/index.d.ts",

src/core/popover.js

@@ -91,6 +91,11 @@ export default class Popover extends Element {
    * @public
    */
   hide() {
+    // If hide is called when the node isn't created yet
+    if (!this.node) {
+      return;
+    }
+
     this.node.style.display = 'none';
   }
 

src/index.js

@@ -145,7 +145,6 @@ export default class Driver {
     }
   }
 
-
   /**
    * Handler for the onResize DOM event
    * Makes sure highlighted element stays at valid position