Change connection string tmate.io -> master.tmate.io
Ubuntu complains without the README
Bug fix: $TMUX wasn't being reused properly
Release 1.8.3
Better error message when SSH keys are not setup
[libssh] auth: If the agent fails, fall back to regular path

It's causing issues on MacOSX when ssh_agent_get_ident_count()
reports "Agent count: 0".
SSH log level is tweakable with -v