[*] 修改消息分发/增加ServerConnection
Merge branch 'master' of https://github.com/zpublic/zpublic
[*] 整理venus_net文件/tcp_client增加检查是否连接的方法/修改server_connection/增加连接关闭原因
Merge pull request #29 from zpublic/sum_circe

Sum circe
& coeus 修正未连接close 导致的崩溃问题