Replace the icypher extension by the official Neo4j driver (with a "runCypher" method)

Once the official Neo4j Python driver has been installed and the `runCypher` has been defined, we can declare cypher queries as:

```python 
runCypher("""
MATCH ... 
RETURN ...
""")
```

Michael Hunger will provide the code from the `runCypher` method.