Added a heading "editing page" in page editor for visual appeal; removed use of alternate <?= ?> syntax in installer as it was causing problems on Win2k3 + PHP/FastCGI. (Experimentally using TortoiseHG's hgtk to commit)

<?php
class Text_Wiki_Render_Plain_Include extends Text_Wiki_Render {    
    function token()
    {
        return '';
    }
}
?>