Method for passing arguments in alias tasks

Instead of this being dumb:

``` js
grunt.registerTask('foo', ['bar', 'baz'])
```

Maybe it can be made smarter re. arguments passing:

``` js
grunt.registerTask('foo', ['bar:$1:$2', 'baz:$*']) // etc
```

Or something. Man, doing this on an iPhone sucks.

The issue names the registerTask API but no files or tests. Start by locating its implementation and current alias-task argument handling, then define the forwarding syntax and semantics before changing anything. Done means positional and all-argument forwarding behavior is specified and verified.

Written by the indexing model from the issue text.