Browser Implementation Fails without Require

Trying to load this in the browser, currently this produces an error

```
Uncaught TypeError: Cannot set property 'setTimeout' of undefined

localhost:8081/node_modules/event-queue/event-queue.js:66
```

at the time that you are trying to initialize it, exports does not exist. I think it has something to do with the opinion that this shouldn't be a standalone component (it seems like you are enforcing the use of require).

Check out http://caolanmcmahon.com/posts/writing_for_node_and_the_browser/

I had started to implement this but some of the [logic at the end of event-queue.js](https://github.com/Gozala/reactor-commonjs/blob/master/event-queue.js#L89) looks too fragile and I cannot understand your intentions clearly enough to be sure I won't break something. It looks like you're intending to throw an error to indicate the user must have require, but the error never throws