AGPUSH-201 "Rename HandshakeMessage to HelloMessage"
Making test class names consistent.
Merge branch 'danbev-AGPUSH-201-rename-HandshakeMessage'
AGPUSH-203 "Notifications with non existing channels should return 200"
Adding PingMessage to protocol and an implementation.
AGPUSH-202 "Implement Ping support"
Merge branch 'danbev-AGPUSH-202-ping-support'