modify (simplify) topic title for displaying in url
<p>I am creating a small message board in PHP and I need to "simplify" the topic title to display it in the url of the topic.</p>

<p>Examples:</p>

<p><code>Ceci est un sujet d'exemple</code> becomes <code>ceci-est-un-sujet-d-exemple</code></p>

<p><code>J'ai été à la plage</code> becomes <code>j-ai-ete-a-la-plage</code></p>

<p><code>I dislike  sp&amp;cial character$</code> becomes <code>i-dislike-spcial-character</code> (if there is a better translation, i take it)</p>

<p>EDIT : All strings must be UTF-8 encoded</p>
