organization in the src structure, modification of README

src/USEFUL/basic_examples/example_doctest.py

@@ -0,0 +1,15 @@
+#!/usr/bin/python
+
+__author__ = "bt3"
+
+'''
+The doctest module automatically runs any statement beginning with >>>
+and compares the following line with the output from the interpreter.
+
+>>> 1 == 1
+False
+'''
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()