#30 Improve support for negative relations

[Anonymous]

At the moment, negative relations are built by prepending a 'does not' before the relationship: e.g.
Nile River does not flow into Indian Ocean.
While this works ok in combination with certain relations such as 'flows into', it results in ugly sentences for other relations such as:
Nile River does not be located in India.

The main reason for this is that it is harder to parse a negated relationship "is not located in" while still detecting that this is the negated form or relationship "is located in".