Build 240722 - massive map performance overhaul

Probably the most rushed update I've ever had, even including the commercial things - not because of the time, but because of the scale. As you could have noticed, since the lighting appeared on map 0, the performance became pretty modest. So, I thought, that's a no-go and needs a quick tweak to make framerates skyrocket again... well, true it needs, though definitely not that quick it appears :) And - yes, the tweaks apply to non-tunnel maps only, mainly map 0. The overall FPS gain is very satisfying, and all the "laggy" spots are gone. Anyway:

• Map renderer completely rewritten along with the vis-checker, now handles instancing faster.
• LOD levels can now differ within DrawIndexedInstanced()-based draw chains.
• LOD levels are set on only one eye rendering in VR and stereo modes in order to remain the same between the half-frames (not that is was too visible at any sane LOD settings - but still cute to have).
• Geometry optimized.
• Static lighting now works only within a model it is assigned to (still casts light on enemies, missiles and you, of course).
• A hack to not have double instances of two very simple textures just because some kB of VRAM make sense.
• Alpha-to-coverage is not just texture-format-triggered, but also requires a flag in the material description of each model part in order to get activated (no more useless A-t-C for some textures encoded "wrong").