The Contributor DataType is going away and it's currently only used in the Evidence resource. We will replace it with publisher, contact, author, reviewer, editor, endorser. The EvidenceVariable resource already has this structure, but we'll explicitly define publisher and contact instead of inheriting it from MetadataResource.

This change is already applied to the EvidenceReport draft resource: http://build.fhir.org/evidencereport.html

Evidence, EvidenceVariable and EvidenceReport Resources have 3 different structures for expressing author, reviewer, and publisher concepts and does not match the handling within MedataResource of other FHIR knowledge resources. There are many different uses for conveying contributorship and stewardship concepts like authors, reviewers and publishers across scientific knowledge artifacts. The FHIR Resource structure enables documentation of these things at the "large" (eg EvidenceReport Resource) and "small" (eg Evidence and EvidenceVariable Resources) levels and there will be many inter-related uses where the implementers do not want to report concepts differently in linked resources.

To support the other needs, extensions to ContactDetail have been created for contactReference, contactAddress and contributionTime.

Changes we want to make:

1. Remove the contributor element from Evidence.
2. Define these elements in Evidence.
        publisher 0..1 string
        contact 0..* ContactDetail
        author 0..* ContactDetail
        reviewer 0..* ContactDetail
        editor 0..* ContactDetail
        endorser 0..* ContactDetail
3. Explicitly define publisher and contact in EvidenceVariable.