`render_OPTIONS` is a method inherited from Twisted, name has been put to lowercase
following massive refactoring, resulting in the method not being called anymore. This
patch fixes it.
the gateway was supposing that comments where emitted from PEP of author. While this is
the case for most blog posts, it's not for comments. Instead the component is now using
`author_jid` which is retrieved by XEP-0277 plugin, and reject the item if the auhor is
not verified (i.e. if `publisher` attribute is not set by XMPP service).
