Moved disclaimer message to email header.
Moved disclaimer message to email header.

This commit moves the disclaimer message to an email header
in a manner similar to how mixmaster does it.

crooks/mixminion,rxcomm/mixminion,rxcomm/mixminion,crooks/mixminion,rxcomm/mixminion,rxcomm/mixminion,crooks/mixminion,crooks/mixminion