Queue an anonymous function with grunt.task.run

I often want to log or cleanup after delegating some work via `grunt.task.run`. This seems like a clean syntax to me:

```
grunt.registerTask('foo', function() {
grunt.task.run(
'beep',
'boop',
function() {
grunt.log.ok('done');
}
});
```

Are there other solutions? I'm thinking of spinning off a plugin and if it goes well, submitting a PR. Is this something you'd welcome in core grunt?