Added DEFAULT_TIMEOUT and RESULT_TTL in settings.RQ_QUEUES

As stated in #57 supports code:

```python
RQ_QUEUES = {
    'default': {
        'HOST': 'localhost',
        'PORT': 6379,
        'DB': 0,
        'PASSWORD': 'some-password',
        'DEFAULT_TIMEOUT': 60,
        'RESULT_TTL': 30,
    },
    'high': {
        'URL': os.getenv('REDISTOGO_URL', 'redis://localhost:6379'), # If you're on Heroku
        'DB': 0,
    },
}
```

You can close #57 and try to think of tests...
Can we restore this to how it was before? To test whether `DEFAULT_TIMEOUT` is parsed properly to `get_queue`, we simply need to define a non default `default_timeout` value in `test_settings.py` and ensure that `get_queue()` a queue with the right `._default_timeout`:
```python
self.assertEqual(get_queue('default')._default_timeout, 123) 
```
I think this is much simpler :)