Implemented pointAt. Used GLM as reference

Sure thing.

Use Case:
In 3D programming you generally need model, view, and projection matrices. pointAt() creates a view matrix which can be thought of as a camera. This matrix basically replaces gluLookAt from the old fixed-function versions of OpenGL.

I uploaded a modified version of the SimpleOpenGL sample to [pastebin](http://pastebin.com/Epyn1kuT) that uses the pointAt function to simulate a Camera moving around an object.