minor: informative references link corrected
new property gr:hasStockKeepingUnit
new property gr:hasStockKeepingUnit
overview table and agent-offering-relation
overview table and agent-offering-relation
overview table and agent-offering-relation
added gr:name
added gr:name
Merge branch 'master' of https://github.com/cKlee/holding-ontology
Merge pull request #8 from cKlee/master

defined some new properties from goodRelation, added overview table