Small fix to #2610

Because that's what it is.

Now it should look the same no matter where the object is located.

In the process found some issues:

- HemisphereLight shading is wrong for objects not in origin, it shouldn't depend on light position amplitude and object position in the scene
- GL errors about uniforms thrown when all lights have "visible = false"
- object dragging in the viewport sometimes hits invisible wall (I guess it's because of limited picking plane size?)
- ArrowHelper doesn't seem to work for (0,-1,0) direction

I wonder how this could happen, built lib from that commit does have corresponding change.

Also fixed spotlights shading in Lambert material and light helpers init colors for light intensities > 1.

Please disregard init scene lighting weirdness, this is just temporary, to be able to test light helpers.

This is for PointLights.

Also removed unused distance property from DirectionalLight class (at least I think so, I know WebGL materials don't use this and I couldn't find it used elsewhere).

But I guess it was already deleted if you were on Windows... :)

Added rays also to DirectionalLightHelper.

Refactored PointLightHelper and DirectionalLightHelper.

Also added one PointLight to dummy starting scene to be able to test point lights (at least while there is no UI for adding lights).

Changed multiple gizmos not to be affected by fog.

Made DirectionalLightHelper constructor take sphere size as a parameter.

Fixes #2600

Not yet 100% sure about all the details but this is something that should be useful for making helpers prettier.

This makes it safer to compile shaders without maxLights cap. Only per vertex phong code path is sensitive to available number of varyings (together with shadow maps, but you would need to be pretty crazy to have enough shadowed lights to hit varying limits).

Also like this phong material behaves more as expected for large polygons.

Performance wise, for many use cases and systems it's actually similar or even faster.