Adding the ability to define multiple hooks in an array. Refs #2

This PR gives the ability to define hooks like so:

```js
var hooks = require('../hook-library.js');

service.before({
  // Use hooks the same way as before with a singular function
  index: hooks.requireAuthAllowPublic,

  // Chain multiple hooks together
  create : [hooks.requireAuth, hooks.setUserID, hooks.setCreatedAt]
});
```

You can still add hooks the exact same way you have always been able to.