[books] new toc title markup

[pkra]

@pkra There's another change as well that I noticed while testing the new appendix markup. In one of those annoying little inconsistencies BITS and JATS abound in, <toc> wants its title in a <toc-title-group>, not a <title-group>.

Originally posted by @davidmjones in #223

[pkra]

For reference, the commit seems to be 9180e95

[pkra]

@davidmjones it looks like some tests files still have the old markup, even when regenerating them.

[pkra]

Ah, I see. \ifNEWappendixes is being used. @davidmjones will you remove those from the code base again soon?