Clean up NER types

```
We currently have a large number of NER types. All except NamedEntity, Organization,
Person and Location should be removed. 

The NER component should be changed to support a type mapping so that a user can set
up a custom finer-grained type system for named entities and map it as desired.
```

Original issue reported on code.google.com by `richard.eckart` on 2012-06-27 20:08:05
