fix panic 1

• fix server: closed chan panic #1

--version

• improve server: -server default to 127.1:22
• improve common: -version show version
• fix release fail #2

positive ack

• improve server: send positive ack if no response after 2 sec timeout
• improve client: after recv-sess update timeout state

first release

v1.0.0

U server.go client.go: add GPLv2 declare