Merge pull request #516 from greezybacon/issue/wrapped-mail-headers

pipe: For wrapped messages, use wrapped headers

Reviewed-By: Peter Rotich <peter@osticket.com>
html2text: Use [title][1] for footnote references
Add flush() call after writes

And allow plugin to support remotely-generated hashes for migration safety
verification
Ensure redirects are complete requests
Ensure HTTP filenames are encoded consistently
Add blocksize concept to the file storage API