`omf cd` command for changing directories.

Jump around Oh My Fish packages and themes using `omf cd <name>`. If no
<name> is specified, jump to oh my fish root folder.

pkg/omf/cli/omf.cd.fish

+# SYNOPSIS
+#   Change the current working directory to plugin / theme home directory.
+#
+# OPTIONS
+#   <name> Name of the package or theme.
+
+function omf.cd -a name -d "Change the current working directory to plugin / theme home directory."
+  if test -z $name
+    pushd $OMF_PATH
+    return 0
+  end
+
+  if test -e $OMF_CONFIG/pkg/$name
+    pushd $OMF_CONFIG/pkg/$name
+  else if test -e $OMF_CONFIG/themes/$name
+    pushd $OMF_CONFIG/themes/$name
+  else if test -e $OMF_PATH/pkg/$name
+    pushd $OMF_PATH/pkg/$name
+  else if test -e $OMF_PATH/themes/$name
+    pushd $OMF_PATH/themes/$name
+  else
+    echo (omf::err)"$name is not a valid package/theme name"(omf::off) 1^&2
+    return $OMF_INVALID_ARG
+  end
+end

pkg/omf/omf.fish

@@ -57,6 +57,18 @@ function omf -d "Oh My Fish"
     case "-h*" "--h*" "help"
       omf.help
 
+    case "c" "cd"
+      switch (count $argv)
+        case 1
+          omf.cd
+        case 2
+          omf.cd $argv[2]
+        case "*"
+          echo (omf::err)"Invalid number of arguments"(omf::off) 1^&2
+          echo "Usage: $_ "(omf::em)"$argv[1]"(omf::off)" <name>" 1^&2
+          return $OMF_INVALID_ARG
+      end
+
     case "l" "li" "lis" "lst" "list"
       omf.list_local_packages | column