[%- # '<=prev | up | next=>' chapters navigation bar
   # expects to be set 
   # nav          - cache navigator object
   # rel_doc_root - relative docs path
-%]
    <table width="100%" border="0" cellspacing="0" cellpadding="0">
        <tr>
            <td align="left" width="50%" nowrap>[%- INCLUDE top_link -%]</td>
            <td align="right" width="50%" nowrap>[%- INCLUDE prev_next_link -%]</td>
        </tr>
    </table>