Document the magic that is linking actions to stores

Hi,

I have been looking at the [testing stores example](https://github.com/goatslacker/alt/blob/master/docs/testing/stores.md) and the associated [repository](https://github.com/jdlehman/alt-example-tests). Conceptually, I think these are very good examples.

I ran into a bit of an issue when I then tried to use this documentation to test my own stores. I was trying to dispatch an event using:

```
alt.dispatcher.dispatch({action: MyActions.someAction, data: {} });
```

This wasn't working.

I eventually discovered that I instead need to pass "action: MyActions.**SOME_ACTION**" instead of "MyActions.**someAction**" and everything started working.

I'd like to request that these special keys (`MyActions.SOME_ACTION`) that point to action functions be made more clear in the documentation. It would have saved me a lot of time if this was explained in the testing stores example. It would also be nice to have this explained in the Actions class documentation.

Thanks!