PROTOCOL: Add a "full" description

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
PROTOCOL: More robust forward compatibility

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
PROTOCOL: Add an optional reason to BYE message

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Use our official "evp" service name

See
http://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xml

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Rename UNIX_SOCKET to EVP_UNIX_SOCKET

Also base it on the service name now

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>