interhg: allow more flexible pattern specification (fixes 2/3 of issue699)
- something else than "pat" followed by a number can be used as key
- something else than "/" can be used as delimiter
- "ilmsux" flags (e.g. "i" for case insensitive) can be used
<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>