Add off method to the editor

package.json

@@ -1,7 +1,7 @@
 {
   "name": "grapesjs",
   "description": "Free and Open Source Web Builder Framework",
-  "version": "0.8.14",
+  "version": "0.8.15",
   "author": "Artur Arseniev",
   "license": "BSD-3-Clause",
   "homepage": "http://grapesjs.com",

src/editor/index.js

@@ -19,6 +19,7 @@
  * * [getContainer](#getcontainer)
  * * [refresh](#refresh)
  * * [on](#on)
+ * * [off](#off)
  * * [trigger](#trigger)
  * * [render](#render)
  *
@@ -448,6 +449,16 @@ module.exports = config => {
       return em.on(event, callback);
     },
 
+    /**
+     * Detach event
+     * @param  {string} event Event name
+     * @param  {Function} callback Callback function
+     * @return {this}
+     */
+    off(event, callback) {
+      return em.off(event, callback);
+    },
+
     /**
      * Trigger event
      * @param  {string} event Event to trigger