Enhancement: Visual representation of spotlights

[0bsidian]

Currently: Drop in a light entity and with it selected, you get an idea of its intensity as represented by a set of spheres in both 2D and 3D views. Convert it into a spot light and you don't get any visual representation at all, it just draws a line from light to target.

Enhancement: Draw a cone for spotlights in both 2D and 3D views. The height of the cone is represented by the distance between light and target. The radius of the cone's base is defined by the entity's radius value.