Bouncing Balls - Fill on Rendered Frame

Currently it will only fill on the frame the collision happened.

However in order to save on the size of the gifs, I only make a frame every n timesteps.

Fix the "contact" variables so they will show Fill for the first rendered frame after a collision timestep.

https://github.com/Kinvert/CUDA-Stuff/tree/master/Simulations/Bouncing-Balls/2D