pass options/withDefaults to coffee-jshint

I want to use coffee-jshint options such as 'browser', then I created little patch.
Could you merge this?

example block of Gruntfile.js:

```javascript
    coffee_jshint: {
      libs: {
        options: {
          jshintOptions: [ 'browser', 'jquery' ],
          withDefaults: true,
          globals: [ 'MyObject1', 'MyObject2' ]
        },
        src: 'coffee/**/*.coffee'
      }
    }
```

> You can set withDefaults:false, but now coffee-jshint has a bug with this option.