Define nodes as Array

This is a very simple change that does not alter the functionality in any way - it simply avoids the need to do a `split` on a `String`, as is the case at present, while also laying out all `nodes` supported in a more readable form.

By the way, awesome project - kudos for putting this together. Shame about the [performance issues you identified](https://github.com/dunxrion/voyeur.js/issues/20), but I am sure at some point in time it should be possible to overcome this limitation.