Return actual Class name rather than namespaced version in search results.

When searching models that are part of an extension, the extension name and model are returned in the results

Previous Behaviour:

```ruby
'Refinery/Page' => 'Page'
'Refinery/Extension/Model' => 'Extension/Model'
```

New Behaviour:

```ruby
'Refinery/Page' => 'Page'
'Refinery/Extension/Model' => 'Model'
```