Proposed commit log message:
[NEW PORT]: mail/managesieve3: Implements an RFC-5804 Manage Sieve client A pure Python client implementation of "A Protocol for Remotely Managing Sieve Scripts", as defined in RFC-5804. WWW: https://bitbucket.org/ericvsmith/managesieve3 Reviewed_by: koobs, mat Approved by: koobs (mentor) Differential_Revision: D16699