new Plugin and Theme functions

functions/Plugin.fish

+function Plugin --argument-names name
+  if [ -e $fish_path/plugins/$name -o -e $fish_custom/plugins/$name ]
+    import plugins/$name
+  else
+    set_color red
+    echo "Plugin '$name' is not installed. Run 'fish install' to download and install it."
+    set_color normal
+  end
+end

functions/Theme.fish

+function Theme --argument-names name
+  if [ -e $fish_path/themes/$name -o -e $fish_custom/themes/$name ]
+    import themes/$name
+  else
+    set_color red
+    echo "Theme '$name' is not installed. Run 'fish install' to download and install it."
+    set_color normal
+  end
+end

oh-my-fish.fish

@@ -9,6 +9,18 @@ if not contains $fish_path/functions/ $fish_function_path
   set fish_function_path $fish_path/functions/ $fish_function_path
 end
 
+if set -q fish_plugins
+  set_color red
+  echo '$fish_plugins usage has been deprecated. Please see https://asciinema.org/a/20802.'
+  set_color normal
+end
+
+if set -q fish_theme
+  set_color red
+  echo '$fish_theme usage has been deprecated. Please see https://asciinema.org/a/20802.'
+  set_color normal
+end
+
 # Add imported plugins, completions and themes. Customize imported
 # commands via the $fish_path/custom directory, for example create
 # a directory under $fish_path/custom/themes with the same name as

templates/config.fish

 # Path to your oh-my-fish.
 set fish_path $HOME/.oh-my-fish
 
-# Theme
-set fish_theme robbyrussell
-
-# All built-in plugins can be found at ~/.oh-my-fish/plugins/
-# Custom plugins may be added to ~/.oh-my-fish/custom/plugins/
-# Enable plugins by adding their name separated by a space to the line below.
-set fish_plugins theme
-
 # Path to your custom folder (default path is ~/.oh-my-fish/custom)
 #set fish_custom $HOME/dotfiles/oh-my-fish
 
 # Load oh-my-fish configuration.
 . $fish_path/oh-my-fish.fish
+
+# Custom plugins and themes may be added to ~/.oh-my-fish/custom
+# Plugins and themes can be found at https://github.com/oh-my-fish/
+Theme 'robbyrussell'
+Plugin 'theme'