[x] Get the unique lightmap textures from ZenKit, as there are many LightMap struct instances referring to the same texture, but with different coordinates.
[x] Group the polygons using the same lightmap together.
[x] Demystify the Zen lightmap coordinates and apply the lightmap correctly to the geometry.
[ ] Make lightmaps work in all scenes.
[ ] Check if indoor scenes can just use the vertex colors instead.
[ ] Evaluate the performance impact of not merging objects with different lightmaps.
[ ] Evaluate the performance impact of not merging lightmapped and non-lightmapped objects.
The indoor spaces are all lit by lightmaps.