import and refine OBI 'disease stage'

[mark-jensen]

As part of the plans to revise relapse and remission (see #104) and to align OBI and OGMS, it is being proposed that OGMS take responsibility for OBI 'disease stage`. The IRI will be maintained and OBI would import it back once we come to agreement on a definition and metadata.

Currently:
disease stage = a part of an occurrence of a disease process which is associated with position in the normal progression of the disease
subclass of biological process

Proposed revision:
disease stage = a process which is a temporal part of some disease course
subclass of process
part_of some disease course
example of usage: Stage IV of Hodgkin disease, Stage 2 prodrome of schizophrenia, Braak Stage II

[zhengj2007]

As what OGMS have discussed, it is kind of achieved agreement that 'disease course' is a biological process. If so, 'disease stage' is also a biological process.

[mark-jensen]

A class for disease stage was previously added to OGMS with the IRI: http://purl.obolibrary.org/obo/ogms.owl#disease_stage

As pointed out in #117, the IRI is badly formed. But, as discussed above, the class IRI should be adopted from OBI and OGMS given curation duties.

@zhengj2007 'disease course', and presumably 'disease stage', are not biological processes. These should be seen more as aggregates of biological processes. An aggregate of things of the same type does not imply the aggregate itself is of the same type. The aggregate of marbles in a pouch is not a marble. Seven baseball games are not a baseball game, but they are a world series.

[BAevermann]

Currently fixing IRIs and this came to my attention. Should I use the OBI IRI or would that cause an up stream collision in OBO, etc?