Docx reader: Change behavior of Super/Subscript

In docx, super- and subscript are attributes of Vertalign. It makes more
sense to follow this, and have different possible values of Vertalign in
runStyle. This is mainly a preparatory step for real style parsing,
since it can distinguish between vertical align being explicitly turned
off and it not being set.

In addition, it makes parsing a bit clearer, and makes sure we don't do
docx-impossible things like being simultaneously super and sub.
Update to current vertalign style, get rid of resolved style.

We'll want to do the resolving in the reader.
It works, but there's a problem with links.
Turn off resolving styles for hyperlinks.