This should at the very least not abort when something weird happens. It
does feel like we should have a type that carries these errors until the
end however as the user might not see them unless they are printed at
the end.

Fixes #310

This is to disambiguate them from markdown links and will be require
with a future release.

(this slows down reloads on modifications)

Closes #335

Make `getPrologue` force `parseParas dflags str` before returning. Without this, it will attempt to read from the file after it is closed, with unspecified and generally bad results.

This also fixes #86.

This was long overdue, now running ./accept.lhs on a clean test from
master will not generate a bunch of changes.