Added 4 Python books and fixed 1 Python book name

Added the following free Python eBooks:
- Learn to Program Using Python ~ By Cody Jackson
- Python Scripting for Computational Science ~ By Hans Petter Langtangen
- Design Patterns In Python ~ By Rahul Verma, Chetan Giridhar 
- Practical Programming in Python ~ By Jeffrey Elkner

Changed "A Beginner's Python Book" to it's proper title: "A Beginner's Python Tutorial"