Remove useless trailing \
Remove trailing spaces
Add missing empty lines

autopep8 -ir -j2 --select=E301,E302,E502,W291,W293,W391 .

Diff quickly checked.

This is recommended by Debian.
closes #618

While this changes constants names, I think it is important as "accused" is
complely wrong. E-mails use the term "Read-receipts" so I chose
to go with RECEIVED.