resolves #724 drop leading & trailing blank lines in verbatim & raw content
Merge pull request #771 from mojavelinux/issue-724

resolves #724 drop leading & trailing blank lines in verbatim & raw content
resolves #773 force encoding of docinfo content to UTF-8
Merge pull request #776 from mojavelinux/issue-773

resolves #773 force encoding of docinfo content to UTF-8
resolves #533 unwrap preamble if standalone