Wikify for semantic wikilinks. Links like `sherry Turkle` become `Sherry_Turkle`

Links like /pages/sherry_Turkle will not get wikified.
Links like http://example.com/sherry_turkle.ogv will not get wikified

Just to check:

    [[ Speaker :: Sherry Turkle | Second Self ]]

should be rendered as:

    <a href="Sherry_Turkle" rel="aa:Speaker">Second Self</a>

no?

Initially, the docs mentioned:

    <a href="/SherryTurkle" rel="aa:Speaker"></a>