front matter etc. will do for now.

I only make major changes (e.g. if the indexes don't have the right
blank spaces) now. Fine tuning will be done separately for txt and html
versions.
No orphaned markup today

I ran the following regex:
<(?!tb)(\w+)>(\n|[^<])+<(?!/\1>)|<(?!/?(tb|sc|[bfgi])>)
Fix -*
Fix comments

Some comments might have to be left in for later if they need fixing
differently in the html and txt versions, but today I'm lucky and they
can all be dealt with straight away.