Handle CGI SSL detection via HTTPS environment better. Some servers send on/off, 0/1, yes/no, and may be upper or lower case. This fix will handle all of those permutations. It was inspired by the detection done in in some other wsgi python web applications I looked at.

<table class="slogEntry parity#parity#">
 <tr>
  <td class="age">#date|age#</td>
  <td class="author">#author|person#</td>
  <td class="node"><a href="#url#rev/#node|short#{sessionvars%urlparameter}">#desc|strip|firstline|escape#</a></td>
 </tr>
</table>