Renderer Upgrade

[Syncaidius]

Rewrite the renderer to make use of multi-threading and up-to-date rendering techniques.

Main points of work:

• [ ] #137
• [ ] #138
  • [ ] #139
  • [ ] #140
  • [ ] #141
  • [ ] #142
• [ ] #143
• [ ] #144
• [ ] #145
  • [ ] #146
• [ ] #147
  • [ ] #148
• [x] #149
• [ ] #150
• [ ] #151
  • [ ] #152
• [x] #153