Support for configuring mocha.setup() using Meteor.settings

settings.json: 

    {
        "public": {
            "mocha_setup_args": {
                "ui": "bdd",
                "globals": ["script*"]
             }
        }
    }

Start meteor using `--settings settings.json`to be able to pass options to `mocha.setup()` 

Using the setup arguments you can target any global leak problems and configure mocha to your likings. (https://github.com/mad-eye/meteor-mocha-web/issues/10)

Also this poses some sort of replacement for a mocha.opts file. (https://github.com/mad-eye/meteor-mocha-web/issues/11)