Chapter 2 Updated - 04/13/11

I've updated Chapter 2 and made the following changes:

• Bug: Inclusion and explanation of Vertex Array Objects (VAOs).
• Content: A brief description of shaders and the included GLSL shaders.
• Content: Descriptions of the CreateShaders and DestroyShaders functions.
• Updated the inline source code as well as the source files to include these changes.

My apologies to those who couldn't get the examples to run on their machines, let me know if you're running into any kind of trouble.