Large projects
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  - Add scripting support (lua?).
  - Tiler and Forge are almost the same, try to refactor them.

 Engine classes
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Scene:
  - Remove uses of g_scene
  - Maybe make Camera a world object instead?

Image:
  - Handle pitch in SDL codec (and all others, actually)
  - Fix the Floyd-Steinberg code in pixels.cpp
  - Add gamma handling in pixels.cpp
  - Port remaining libpipi files from src/image/todo/: