add merge-stream to devDependencies

Author: Rokt33r

package.json

@@ -68,6 +68,7 @@
     "grunt": "^0.4.5",
     "grunt-electron-installer": "^1.2.0",
     "history": "^1.17.0",
+    "merge-stream": "^1.0.0",
     "nib": "^1.1.0",
     "react": "^0.14.3",
     "react-css-modules": "^3.7.6",