Add npm@3 as a devDependency

cause it is.

Author: imlucas

package.json

@@ -149,6 +149,7 @@
     "mongodb-js-precommit": "^0.2.8",
     "mousetrap": "^1.5.3",
     "node-notifier": "^4.3.1",
+    "npm": "^3.4.0",
     "numeral": "^1.5.3",
     "octicons": "https://github.com/github/octicons/archive/v3.1.0.tar.gz",
     "pluralize": "^1.2.1",