somewhat tighter definition for xref and uri; fixes #131
somewhat tighter definition for xref and uri; fixes #131

hattrill/go-site,hattrill/go-site,geneontology/go-site,hattrill/go-site,hattrill/go-site,geneontology/go-site,geneontology/go-site,geneontology/go-site,geneontology/go-site,hattrill/go-site