Add shell extension

Author: ERSUCC

extensions/shell-1.0.3.zip

@@ -316,6 +316,14 @@ Secondly, it means not having to carry around external files (like CSV or GIS da
     version:          "1.1.0"
     homepage:         "https://github.com/NetLogo/SendTo-Extension"
   }
+  {
+    name:             "Shell"
+    codeName:         "shell"
+    shortDescription: "Run shell commands, read and write environment variables"
+    longDescription:  ""
+    version:          "1.0.3"
+    homepage:         "https://github.com/NetLogo/Shell-Extension"
+  }
   {
     name:             "Simple R Extension"
     codeName:         "sr"