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Added an enhanced Publication model
Replaced biolink-model.owl with biolink-model.owl.ttl
Differentiated mappings for classes into related, broad, narrow, close, and exact mappings
Differentiated mappings for slots into related, broad, narrow, close, and exact mappings
Fixed typos in class and slot definitions
Fixed inconsistent domain and range constraints
Added classes to represent food
Fixed parent for relation enables
Deprecate edge_label in favor of predicate
Added missing prefixes
Added guidelines to the documentation
Tidied the representation and use of mixins
Differentiated the mixin hierarchy from the class hierarchy
Rearranged properties like id, name, type, description to a generic grouping entity class