Update README files.

[CONFIGURATION]
* NEW: Update README files.

README

@@ -42,6 +42,10 @@ The following pieces of code were borrowed and adapted:
   by Denys Vlasenko and Bernhard Reutner-Fischer. See https://www.busybox.net/
   for more details.
 
+- The stock icons flags were generated from SVG files taken from
+  https://github.com/smucode/react-world-flags. They are published under the MIT
+  license.
+
 If I forget some borrowed code in the list above, just tell me.
 
 Enjoy Gambas!

README.md

@@ -48,6 +48,10 @@ The following pieces of code were borrowed and adapted:
   by Denys Vlasenko and Bernhard Reutner-Fischer. See https://www.busybox.net/
   for more details.
 
+- The stock icons flags were generated from SVG files taken from
+  https://github.com/smucode/react-world-flags. They are published under the MIT
+  license.
+  
 If I forget some borrowed code in the list above, just tell me.
 
 Enjoy Gambas!