enable passing kb settings as keyword args instead of config file

instead of being forced to do 

```python
kb = KnowledgeBase(configuration_file)
```

I want to be able to do

```python
KnowledgeBase(reader='sparql_protocol', writer='sparql_protocol', server='localhost', endpoint='http://nlp.dainst.org:8888/sparql', port=8888, default_context='http://purl.org/hucit/kb')
```

Need to determine what's the minimum subset of parameters if any