in-line review comments

I changed the {{Review}} template slightly to allow multiple
entries/paragraphs.  Following normal wiki conventions, if you want to
reply to a Review, add to the end of it like this (right before the
closing "}}")

     ----
     ~~~~: This is my addition....

The ~~~~ will get turned into your name and the current time.

(I know, it's not perfect!)

For an example, see
    http://www.w3.org/2007/OWL/wiki/XML_Serialization#The_XML_Schema

(although maybe that whole review will be removed shortly, since it's
now obsolete)

    -- Sandro