Firefox title fix

For some reason the document fragment that represents the opf file, when searched with jquery, doesn't work at all. I suspect it might be some namespace issue, because it seems okay on non-namespaced nodes. Not even the XSL/XPath machinery worked in firefox, even though it all worked flawlessly in Chrome. In the end I found that  querySelectorAll works, so I fixed both the title and bookid to use that instead.

Also fixed a spelling mistake in the opf file. This unfortunately means we generated books that aren't compliant, as they don't have a unique-identifier attribute on the package tag in the opf file.