Add karma-firefox-launcher

Author: wesleycho

package.json

@@ -12,7 +12,8 @@
     "grunt-karma": "~0.8.2",
     "grunt-contrib-jshint": "~0.10.0",
     "karma-jasmine": "~0.2.2",
-    "karma-chrome-launcher": "~0.1.3"
+    "karma-chrome-launcher": "~0.1.3",
+    "karma-firefox-launcher": "~0.1.3"
   },
   "scripts": {},
   "repository": {