Update tmux conf for tmux 2.5
Update tmux conf for tmux 2.5

https://github.com/tmux/tmux/issues/592#issuecomment-260541974
https://github.com/tmux/tmux/commit/76d6d3641f271be1756e41494960d96714e7ee58

loganlinn/dotfiles,loganlinn/dotfiles,loganlinn/dotfiles,loganlinn/dotfiles