Update npm version to latest 2.x

Update npm version to latest 2.x as the old one (2.6.1) has some bugs that prevent us from using git urls, installing some plugins, etc.

Author: rosen-vladimirov

package.json

@@ -54,7 +54,7 @@
     "mute-stream": "0.0.5",
     "node-inspector": "https://github.com/NativeScript/node-inspector/tarball/v0.7.4.0",
     "node-uuid": "1.4.3",
-    "npm": "2.6.1",
+    "npm": "2.14.12",
     "open": "0.0.5",
     "osenv": "0.1.3",
     "plist": "1.1.0",