adding knowledge graph links with different semantics

Currently the semantics of the edges in the two relation graphs is:
- `X rdfs:subClassOf Y` means `X SubClassOf Y`
- `X R Y` (if `R` != `rdfs:subClassOf`) means `X SubClassOf (R some Y)`

If a user is querying the "nonredundant" relation graph, they can propagate these relations in a consistent way down and up the class hierarchy within SPARQL, e.g.:

```
?x results_in_development_of:/rdfs:subClassOf* ?y
```

It could be useful to add more kinds of links that would have different semantics from those:
- `X owl:disjointWith Y` --> `X DisjointWith Y`
- `X RO:0002161 Y` ('never in taxon') --> `X SubClassOf (not (RO:0002162 some Y))` ('in taxon')
- `X RO:0002175 Y` ('present in taxon') --> `_:anon_individual Type (X and (RO:0002162 some Y))` ('in taxon')

All of those have different propagation characteristics with regard to the class hierarchy, compared to the existing types of edges.

We can compute the complete closure and a nonredundant version of each of those links (maybe as new features in relation-graph). Should those triples go in different graphs? Or just the same two relation graphs and add the expansion semantics to the docs?

Start by reviewing the existing two relation graphs and the relation-graph closure and nonredundancy behavior described in the issue. Compare the proposed owl:disjointWith and taxon-link semantics with the current SPARQL propagation example. Done requires deciding whether these links use separate graphs or documented expansions and specifying the resulting semantics.

Written by the indexing model from the issue text.