Grunt task

From the tested project's Gruntfile:

```
grunt.initConfig({
    intern: {
        someReleaseTarget: {
            runType: 'runner', // defaults to client
            config: 'my/package/tests/intern.js',
            ... // any other supported options
        },
        someOtherReleaseTarget: { ... }
    }
});
...
grunt.loadTasks('path/to/intern/grunt');
...
grunt.registerTask('default', ['intern'], ...);

Will add detailed documentation to the Wiki when / if this is approved.