Double tmux's history-limit
Break $PATH export into several lines
Refactor window printing into function `__print_to_window`
MINOR: Improve formatting of Fish configuration
Guard call to 'rbenv' with 'command'

This prevents Fish from using builtins or defined functions.
Don't print spaces between arguments to 'echo'
Rewrite 'fish_prompt' with __fish_git_prompt builtin