v0.1.0

First version.

• Resumable sessions: a TCP connection survives the loss of every WebSocket
  path as long as a new one connects within the resume timeout.
• Several paths per session for instant failover.
• Shared-token authentication, per-session secrets, and limits on sessions,
  paths and buffered data.
• resumux server and resumux client, with JSON config files.
• Several server URLs per client, so a session's paths can take different
  routes, such as different CDN edges or a CDN and a direct address.
• A clean close half-closes each path and waits briefly for the peer, so the
  last acknowledgement is not lost to a connection reset.
• -proxy-protocol tells the target each client's address with a PROXY
  protocol v2 header. A proxy's client-address header is used only on
  requests from -trusted-proxies.
• flakyproxy -freeze silences a connection without closing it.
• -max-sessions-per-client and -max-new-sessions-per-client stop one
  address from taking every session, which matters when the token ships
  with a public client. They never apply to resuming a session.
• A refused handshake reports the server's reason, such as which limit was
  hit.
• flakyproxy -delay -jitter -hiccup-every imitates a long, lossy route.
• -redundant on the client copies frames to a second path while at most
  64 KiB is unacknowledged, so a lost or stalled packet does not freeze an
  interactive stream. It is negotiated with the Resumux-Redundant header;
  -refuse-redundant lets a server decline it.
• -listen on the server takes several addresses, such as :443,:8443.