Prepare GLM

3D graphics programming makes heavy use of vector and matrix algebra. For that
reason, use of openGL is greatly facilitated by accompanying it with a function
library or class package to support common mathematical tasks. The most frequently
used library for such a purpose is openGL Mathematics, usually called GLM.

GLM is a header-only C++ library compatible with Windows, Macintosh, and Linux.
GLM commands conveniently use the same naming conventions as those in openGL,
making it easy to go back and forth when reading C++ and GLSL code used in a
particular application.

GLM provides classes and basic math functions related to graphics concepts, such
as vector, matrix, and quaternion. It also contains a variety of utility classes
for creating and using common 3D graphics structures, such as perspective and
look-at matrices. It was first released in 2005, and is maintained by Christophe
Riccio.

Visit glm.g-truc.net/0.9.9/index.html to download the zip file of the latest
version of GLM (glm-0.9.9.7.zip) that includes release notes. The download folder,
after being unzipped, contains a folder named "glm". That folder (and its contents)
is the item that we will need to use.