Map of example scripts to Chapter sections

1. Pure C extensions
  1.1 ./fibonacci_c/*
  1.2 ./fibonacci_c_error_handling/*
  1.3 ./fibonacci_c_releasing_gil/*

2. Cython as a source to source compiler
  2.1 ./fibonacci_cythonize/*
  2.2 ./fibonacci_cythonize_optionally/*

3. Cython as a language
  3.1 ./fibonacci_cython/*
  3.2 ./fibonacci_cython_nogil/*

4. Calling C functions using ctypes
  4.1 ./ctypes_libc_printf.py
  4.2 ./ctypes_qsort.py

5. CFFI
  5.1 ./cffi_qsort.py
