Expose `eyes.typeOf` 

See: https://github.com/nodejitsu/cliff/issues/2#comment_1328724

``` js
function typeOf(value) {
```

to become

``` js
eyes.typeOf = function typeOf(value) {
```

This would be really helpful to me for this issue: https://github.com/nodejitsu/cliff/issues/2#comment_1328724 ... I will be copy / pasting this helper in the meantime and exposing it there. 
