Document SchemaCachingInferencer as the preferred alternative to the ForwardChainingInferencer

[abrokenjester]

The new SchemaCachingInferencer should be documented as the preferred alternative for most use cases as it outperforms the ForwardChainingInferencer.

There is an open question about whether there are use cases in which the old inferencer is still the better choice. The fact that the new inferencer uses SERIALIZABLE locking exclusively and is therefore effectively single-threaded on updates is a worry, though I imagine that even with that restriction in place it will still outperform the old reasoner in most scenarios. If that is the case, I think we should just bite the bullet and document this as the preferred default inferencer in the reference documentation.