split a pane and keep the cwd

[nedtwigg]

It has happened a few times where I have split a pane, and wished that it would open the new shell with the cwd I'm in right now.

In tmux, you can get this behavior by putting this into ~/tmux.conf

bind '"' split-window -v -c '#{pane_current_path}'
bind %   split-window -h -c '#{pane_current_path}'
bind c   new-window      -c '#{pane_current_path}'

This utilizes the "tmux format variables" feature. If we add this feature, I think I'd prefer to just have a splitting keeps cwd checkbox.