allows batch registration of several commands for a single event

Adds the possibility to register several commands to the same event in batch:

```js
commands: {
    "appEventFooBarBaz":    [
        FooCommand,
        BarCommand,
        BazCommand
    ]
```

Sequentially handled.

Didn't bump the version number, nor build the .min file. And sorry 'bout the EOL shizzle. You can view the proposed changes without whitespace diffs by appending `&w=1` to the URL.