Minor tweaks to allow cleveref's poorman .sed files to work better

We'll still need to patch them to deal with autoref vs cref, but at
least we won't error or have missing braces.

The poorman option to cleveref was the only way I've found to get
htlatex to compile the book.
Merge pull request #662 from JasonGross/allow-poorman-cleveref

Minor tweaks to allow cleveref's poorman .sed files to work better