Bumping to moment v2.1.0

If this doesn't get merged, you can use this version by changing the `moment` section of `smart.json` (in your meteor project root) to look like this:

    packages : {
      "moment": {
        "git": "https://github.com/acreeger/meteor-moment.git",
        "branch": "v2.1.0"
      },
      // your other packages here
    }