Eclipse Entension bean handler does not handle primitives correctly.

Originally reported on Google Code with ID 74

```
ExtensionBeanHandler#valueOf is invoked when a primitive type is defined in the extension
point. However it tests the class against the wrapper class rather than primitive class;
i.e. Integer.class rather than int.class.

These means primitive types cannot be used.
```

Reported by `drsgoodall` on 2012-06-22 10:16:45
