Dev edition todos

[domenic]

I spent some time today trying to re-create the dev edition from scratch using the Wattsi-produced output.

Here are the big to-dos I found:

• In headings and the TOC, section numbers need to be wrapped with <span class="secno">
• Splitting should be massively improved to give an outcome as good as the current dev edition. Probably every second-level section (e.g. 4.13) would get its own file.

Here are the minor todos that are fixable in postprocessing but maybe Wattsi should fix:

• Don't output both the brief TOC and the full TOC. Just the full TOC suffices (with a single "Table of Contents" heading).
• Remove the onload attribute from body.
• Body should get an "index" class for the TOC page (index.html)

(This is my third time trying to submit this, so if GitHub suddenly comes back from its stupor and three of these issues show up, please delete two of them...)

[domenic]

Dupe of #27.