Fixed bugs

src/background.js

 
 	var xhr = new XMLHttpRequest();
 	xhr.onload = () => {
-		AKS.actionIcons = JSON.parse(this.response);
+		AKS.actionIcons = JSON.parse(xhr.response);
 		completeInitialization();
 	};
-	xhr.open('GET', chrome.extension.getURL('/action_icons.json'), true);
+	xhr.open('GET', chrome.extension.getURL('action_icons.json'), true);
 	xhr.send();
 }
 
-initialize;
+initialize();