Added Al Sweigart's newest free book, "Automate the Boring Stuff", starting at chapter 0. You could use http://automatetheboringstuff.com instead of http://automatetheboringstuff.com/chapter0/ but I figured chapter 0 would be more appropriate due to it being the first page of the book and both links have the navigable table of context.

Added a new book category "Competitive Programming". And added to it a book "Competitive Programming" by Steven Halim, Freely downloadable from his page on the National University of Singapore.

Added Lecture Notes of Dr. Arbind K Lal, IIT Kanpur

Lecture Notes of Linear Algebra (MTH101) by Dr. P. Shunmugaraj of IITK

Book name changed from "Problem Solving with Algorithms and Data Structure" to "Problem Solving with Algorithms and Data Structure using Python"

Problem Solving with Algorithms and Data Structure - Brad Miller and David Ranum, Luther College

that contains nice OpenGL learning materials.