Update karma to 0.13.19

Fixes error with socket.io mentioned in issue karma-runner/karma#1782

Author: tfoxy

package.json

@@ -34,7 +34,7 @@
     "codacy-coverage": "1.1.3",
     "coveralls": "2.11.4",
     "es6-promise": "3.0.2",
-    "karma": "0.13.14",
+    "karma": "0.13.19",
     "karma-browserstack-launcher": "0.1.6",
     "karma-chai": "0.1.0",
     "karma-chrome-launcher": "0.2.1",