Merge pull request #118 from Virtex6/patch-1

Fetch submodule posix_tz_db as recursive submodule of gui

Author: glynhudson

readme.md

@@ -414,7 +414,7 @@ In addition, the GUI is now maintained in a [separate repository](https://nodejs
 If the `gui` directory is empty, use the following to retrieve the GUI source and fetch the dependencies:
 
 ```shell
-git submodule update --init
+git submodule update --init --recursive
 cd gui
 npm install
 ```