Updated copyright notices to include the year 2018.
submission-login: Fail CLIENT_AUTH_RESULT_MECH_SSL_REQUIRED authentication result with 523 5.7.10 error. Defined in RFC5248, Section 2.4.
submission-login: Fix pipelining of commands beyond AUTH. The master_data_prefix was initialized wrong; it omitted the expected '\0' byte after the helo field.
submission-login: use container_of instead of casts
submission-login: remove unnecessary casts Casting from a void * to any pointer type is automatic and doesn't require an explicit cast.
Implemented SMTP submission proxy service.