Fix issue 12 - multiple api support

The ```TASTYPIE_SWAGGER_API_MODULE``` settings can be dropped in favor of a new urls.py format:

```python
url(r'api/myapi/doc/',
        include('tastypie_swagger.urls', namespace='myapi_tastypie_swagger'),
        kwargs={"tastypie_api_module":"myapp.registration.my_api", "namespace":"myapi_tastypie_swagger"}),
```

The namespace has to be repeated in the kwargs as we cannot access it from the view. If someone has a better idea, I'd be glad to hear from you :-)