Comment doesn't contain reference to original Post

[white-gecko]

If I post a comment, the resulting resource doesn't contain a predicate which refers back to the original post, but it should contain one (sioc:reply_of).

Also add a sioc:has_reply to the original post.

http://www.sioc-project.org/ontology#term_reply_of
http://www.sioc-project.org/ontology#term_has_reply

[white-gecko]

The sioc:has_reply should be added after a received ping.

[white-gecko]

reply_of property added in f4b071e