Titles with an ampersand are not handled properly

[gallais]

'&' is a special symbol in sed directives so a title containing ampersand (among other things)
will mess up the call to sed splicing the title in between <title></title>.

Cf. http://impega.github.io/reciptacle/Crumble.html for an example:

<title>Crumble Poire <title> Pomme - Reciptacle - Hurray!</title>

A principled solution would be to escape special characters in the title (I suspect / probably
also leads to issues).