Important stuff
---------------
[ ] Something to move a character around.
  - [ ] Joystick input.
  - [ ] Event listeners for keyboard or joystick.
[ ] Map collisions?
[ ] Add scripting support (lua?).
[ ] Open several maps at the same time.
[ ] See whether we should use floats or at least subpixel coordinates for
    on-screen objects, in order to handle velocity and other physics stuff
    (with rounding when displaying, of course)

Performances
------------
[ ] Switch rendering to vertex/index buffer objects

Editor
------
[ ] File requester for maps.
[ ] Scroller/panner for maps.
[ ] Allow to modify maps.
[x] Do GTK stuff instead of waiting for the framerate
[ ] "map viewer" object/asset, as opposed to more complex in-game manager

Specs
-----
[ ] Write a map file format.
[ ] Add special zones to the map.

Architecture
------------
[ ] Tiler and Forge are almost the same, try to refactor them.