20160130:
- add: program structure, code coming from DGEM and 2048.
- add: sprites for ship, ship mods, all weapons, background level 1.
- add: for now, only ship moves, background is scrolling.

20160131:
- fix: crash for some window events.

20160205:
- fix: highscores window opening xywh.
- fix: random crash in background stars display.
- fix: desk background: color and set at start.
- add: palette management.

20160207:
- add: front, rear and sides blasts, rear blaster.
- key: shift for fire.

20160212:
- add: sides canons and bombs.
- add: sides lasers.

20160213:
- add: homers (for now, automatic target is mouse cursor).
- add: front missiles.
- add: side flame thrower.

20160218:
- add: small and large mines.
- add: front double blaster.
- add: front laser.
- add: front flamer.
- key: s = enable/disable shield, p = inscrease power.

20160322:
- add: call for st-guide documentation.
- add: level 1 graphics.

20160327:
- add: level editor.

20160330:
- chg: revamped preferences window.
- add: display inanimated items from level map.

20160401:
- fix: backgroud stars differential moves.
- add: backward scrolling.
- add: collision with map items (scenery is blocking moves).
- key: q = simple/double ship speed (quicker moves).

20160404:
- fix: empty path for preferences file if $HOME is not set.

20160422:
- fix: memory problems (sizes and indexes) in load/save maps functions.
- mod: maps uses mxallocated arrays instead of GFA internal DIM.
- fix: background display under monoTOS.

TODO:
- add: map items animations, creatures.
- fix: drones positions.
- add: loots, credits, lifes.
- add: joystick support (and gamepads ?).
- etc