[patch] anchors on all headers

Since W3C pubrules [1] now require that *all* headers have an anchor,
I patched xmlspec.xsl to add <a name=""> to all headers that did not
have one already. That is:

- the document title (<h1>), name="title"
- the document subtitle (<h1>), name="subtitle"
- the document type (<h2>)   name="w3c-doctype"
- the appendix section title (<h2>). name="appendices"
- example titles (<h5>) for non-tabular examples. name="{generate-id()}"
- scrap heads (<h5>). name="{generate-id()}"

Diff file attached.

MaxF.