GobAnim vs. GobAnim

Something went 'oops' when trying to upgrade the 'bouncing feet' behaviour for dumblador's behaviour. I edited new animations for the feet in AnimEDS (mostly to take advantage of the bounding box edition feature), but when I injected that into the ongoing test level, I simply didn't see any feet anymore.

Armé de mes nouvelles petites anim' pour les pieds baladeurs de Dumblador (et des zones de collisions associées), je venais tout juste de faire les ajustements à blador.cmd, mais en lançant le jeu dans l'émulateur, j'ai juste eu droit à une avalanche de "oops? endless looping" sur la console de débugging. Un p'tit breakpoint bien senti sur iprintf (oui, carrément) m'a permis de voir que je faisais fausse route: ce sont des GOBs "simples" (comme dans AppleAssault) qui sont créés pour les pieds et non pas des CompoundGobs comme Bilou et Dumbladors. Du coup, l'interprétation des données d'animation est erronnée. Je vais devoir passer plus de temps que prévu sur ce point-là.

I had to rely on some DDD to figure out that gob shooting currently systematically create a SimpleGob instance, but that attaching a AnimEDS animation to a SimpleGob just results in non-sense (and likely no display). I thus have to merge a bit more those two co-existing animation parsing (binary and textual) and rendering (compound or simple). The easy way out would be to claim "oh, I can also shoot compound gobs", but the reality is that 90% of shots (weapons, dustballs, feet) will be simple gobs. Only monster generators and Bosses may need something else.

• [done] GobAnim::parse() should use AnimUser encoding, rather than AnimCommand {} structs. Keep the API (GobScript syntax) unchanged.
• [done] SimpleGob::play() should align to that new encoding.
• [done] enable BBOX, origin and pageno's colours bits from anims.
• [ok] ensure a 1-limb AnimEDS encoding can be used to create SimpleGobs in GameScript::GobCommand() 
• [done] GameScript::setGobState() no longer blindly cast to SimpleGob to call setstate()
• [done] GobGun::shoot() no longer blindly generates SimpleGob()s