Added Visual Studio Code plugin

Only required on Mac OS X. More details here:

https://code.visualstudio.com/Docs/editor/setup

plugins/available/visual-studio-code.plugin.bash

@@ -0,0 +1,12 @@
+cite about-plugin
+about-plugin 'Defines the `code` executable for Visual Studio Code on OS X'
+
+# Based on https://code.visualstudio.com/Docs/editor/setup
+if [[ `uname -s` == "Darwin" ]]; then
+  function code () {
+    about 'Starts Visual Studio Code in the provided directory'
+    group 'visual-studio-code'
+
+    VSCODE_CWD="$PWD" open -n -b "com.microsoft.VSCode" --args $* ;
+  }
+fi