Visualize collision models

[chendeni]

I have a request for a new feature. When creating collision for custom planets, how do you know if there are any unwanted slippery spots and whether there are any invisible holes in the surface?
By enabling the collision renderer, it would show the collision model of every object, color coded by collision type. Depending on gravity and the normals of each polygon, it will also show whether the surface is slippery and whether it can be wall jumped.