Started to implement collision response

We have started to implement the collision response method mentioned in our previous blog post. To our help we have used the inertia tensor of a solid sphere, which we found in this Wikipedia article: https://en.wikipedia.org/wiki/List_of_moments_of_inertia#List_of_3D_inertia_tensors.

The response seems to work partially, where the balls collide with and are stopped by the planes, but no bouncing seems to occur. This can be seen in the video below.