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

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

themes/idan/README.md

-## idan
-A functional, uncluttered fish theme with usability perks for git users and python developers.
-
-
-![Screenshot of idan theme](https://f.cloud.github.com/assets/22723/544512/14b7cd6e-c251-11e2-82c0-d5b4f41581c7.png)
-
-
-#### Characteristics
-
-##### Left Prompt
-
-* Current python virtualenv (if applicable)
-* Truncated CWD (just the current folder name)
-* Git branch and dirty state (if applicable)
-
-##### Right Prompt
-
-* Full CWD path
-* Last error code (if applicable)

themes/idan/fish_prompt.fish

-# name: idan
-# Display the following bits on the left:
-# * Virtualenv name (if applicable, see https://github.com/adambrenecki/virtualfish)
-# * Current directory name
-# * Git branch and dirty state (if inside a git repo)
-
-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 -o cyan)
-  set -l yellow (set_color -o yellow)
-  set -l red (set_color -o red)
-  set -l blue (set_color -o blue)
-  set -l green (set_color -o green)
-  set -l normal (set_color normal)
-
-  set -l cwd $cyan(basename (prompt_pwd))
-
-  # output the prompt, left to right
-
-  # Add a newline before prompts
-  echo -e ""
-
-  # Display [venvname] if in a virtualenv
-  if set -q VIRTUAL_ENV
-      echo -n -s (set_color -b cyan black) '[' (basename "$VIRTUAL_ENV") ']' $normal ' '
-  end
-
-  # Display the current directory name
-  echo -n -s $cwd $normal
-
-
-  # Show git branch and dirty state
-  if [ (_git_branch_name) ]
-    set -l git_branch '(' (_git_branch_name) ')'
-
-    if [ (_is_git_dirty) ]
-      set git_info $red $git_branch " ★ "
-    else
-      set git_info $green $git_branch
-    end
-    echo -n -s ' · ' $git_info $normal
-  end
-
-  # Terminate with a nice prompt char
-  echo -n -s ' ⟩ ' $normal
-
-end

themes/idan/fish_right_prompt.fish

-# Display the compressed current working path on the right
-# If the previous command returned any kind of error code, display that too
-
-function fish_right_prompt
-  set -l last_status $status
-  set -l cyan (set_color -o cyan)
-  set -l red (set_color -o red)
-  set -l normal (set_color normal)
-
-  echo -n -s $cyan (prompt_pwd)
-
-  if test $last_status -ne 0
-    set_color red
-    printf ' %d' $last_status
-    set_color normal
-  end
-end