Quick code simplification

Hey @npvn!

Just a few minor changes to the actual code.

I like how short and sweet everything is.

The one thing I would also change is that currently Saasu acts as a singleton because it copies properties onto the one instance of itself. 

To make it more flexible it would be nice to be able to do something like:

```
var saasuAccountOne = Saasu.init({ ... })
var saasuAccountTwo = Saasu.init({ ... })
```

But this is not a high priority at the moment.

Thoughts?