Implement tmux window switching for nested tmux sessions.

[merijn]

Transparently transition between windows of nested tmux sessions.

[merijn]

http://robots.thoughtbot.com/seamlessly-navigate-vim-and-tmux-splits

[merijn]

https://github.com/christoomey/vim-tmux-navigator

[merijn]

http://stahlke.org/dan/tmux-nested/

[merijn]

https://github.com/aleclearmind/nested-tmux