1.去除推流等功能，仅保留手写板支持
  2.wss server由TLS 1.0 改为TLS 1.2
  source git: http://123.56.226.173/hubin/liveAssistant.git
  branch: liveserv
  commit   3972fa63f0c3f38a9d74cb7bb4c15f4cd52fe0fa