Add README content for the hello world.

Author: jonathanrocher

stage4.0_first_application/README.md

@@ -1 +1,10 @@
 # Hello world in ETS pyface!
+This folder contains a "hello world" application using ETS' pyface package. To 
+execute it, 
+- an application object defines a custom application next to a `main.py` script 
+  which executes it. 
+- The content of the application is a single Task which contains a single 
+  TraitsUI-based pane displaying a model's string content.
+
+Optional: If you want to get ahead, continue on and add a dock pane (still 
+traitsUI based) which displays "hello world" as a left side panel.