Rewrite of str:replace

Nick Wellnhofer <[email protected]> Wed, 01 Aug 2012 00:33:01 +0200

Newsgroups	gmane.comp.gnome.lib.xslt
Message-ID	<[email protected]>

I just found an old patch of mine. It makes the str:replace extension 
function standard-conformant. See 
https://bugzilla.gnome.org/show_bug.cgi?id=569703. I committed it on top 
of my other fixes on Github.

Daniel, if you like, I can send you all my changes as single patches.

Nick