Large projects
----------------

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

 Engine classes
----------------

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
  - Make some Image::Lock2D method that returns an Array2D
  - port libpipi files:
     · analysis/histogram.cpp
     · analysis/measure.cpp
     · codec/coreimage.cpp
     · codec/coreimage.h
     · codec/jpeg.cpp
     · combine/blit.cpp
     · combine/merge.cpp
     · combine/minmax.cpp
     · combine/mulscreen.cpp
     · combine/rgb.cpp
     · combine/subadd.cpp
     · context.cpp
     · filter/blur.cpp
     · filter/rotate.cpp
     · filter/transform.cpp
     · filter/wave.cpp
     · paint/bezier.cpp
     · paint/floodfill.cpp
     · paint/line.cpp
     · quantize/reduce.cpp
     · sequence.cpp