[split] Move gianu theme to oh-my-fish/theme-gianu

https://github.com/oh-my-fish/theme-gianu

themes/gianu/README.md

-## Gianu
-
-Original theme made by [gianu](https://github.com/gianu) for oh-my-zsh, converted to oh-my-fish by [JBarberU](https://github.com/JBarberU)
-
-![gianu theme](https://cloud.githubusercontent.com/assets/1499062/5955321/114b64d2-a7a2-11e4-8732-e8cf06903314.png)
-
-
-#### Characteristics
-
-Displays:
-
-* Username and hostname
-* Working directory
-* Git information when available.

themes/gianu/fish_prompt.fish

-# name: Gianu
-function _git_branch_name
-  echo (command git symbolic-ref HEAD ^/dev/null | sed -e 's|^refs/heads/||')
-end
-
-function _is_git_dirty
-  echo (command git status -s --ignore-submodules=dirty ^/dev/null)
-end
-
-function fish_prompt
-  set -l cyan (set_color cyan)
-  set -l yellow (set_color -o yellow)
-  set -l red (set_color -o red)
-  set -l green (set_color -o green)
-  set -l white (set_color -o white)
-  set -l normal (set_color normal)
-
-
-  set -l cwd $cyan(basename (prompt_pwd))
-
-  if [ (_git_branch_name) ]
-    set -l git_branch $green(_git_branch_name)
-    set git_info "$normal($green$git_branch"
-
-    if [ (_is_git_dirty) ]
-      set -l dirty "$yellow ✗"
-      set git_info "$git_info$dirty"
-    end
-
-    set git_info "$git_info$normal)"
-  end
-
-  echo -n -s $normal '[' $white (whoami) $normal '@' $red (hostname -s) $normal ' ' $cwd ' '  $git_info $normal ']$ ' 
-end
-