Add visuals that will help understand and debug the simulation

[avihuxp]

For example:

1. Add the ability to show a given boid's field of view
2. Add the ability to show cells of the quadtree or the spacial hashing table.
3. Add the ability to show for each boid its neighbors
4. Add the ability to display the vectors for each steering force, color coded
5. Add the ability the pause the simulation and then resume