add rdf 0.9.0
Merge branch 'master' of https://github.com
rdf: add missing dep on yojson
update md5 of rdf 0.9.0
Merge branch 'master' of https://github.com/OCamlPro/opam-repository
Merge branch 'master' of https://github.com/OCamlPro/opam-repository
change archive checksum or rdf 0.9.0
Merge branch 'master' of https://github.com/OCamlPro/opam-repository
Merge pull request #2776 from zoggy/master

add rdf 0.9.0