Add :role to BIBO

[kcoyle]

Role is a property used in the Person and the Organization shapes in SRAP. It defines the role of an agent in relation to the scholarly work. The role property takes an identifier for a role from an authoritative list.There are some specific roles defined in BIBO but those are not sufficient. SRAP recommends that role identifiers be taken from the Library of Congress list of relators.

Recommendation:

• Add a role property to BIBO as an object property.