Explicitly install Karma browser launchers

Author: porada

package.json

@@ -10,6 +10,9 @@
   "devDependencies": {
     "karma": "~0.12.16",
     "karma-jasmine": "~0.1.5",
+    "karma-phantomjs-launcher": "~0.1.4",
+    "karma-chrome-launcher": "~0.1.4",
+    "karma-firefox-launcher": "~0.1.3",
     "grunt": "~0.4.2",
     "grunt-contrib-concat": "~0.4.0",
     "grunt-karma": "~0.8.3",