Fixed inventory.
Patche question system. Need some refactoring...
Fixed reload on death.
Fixed ccl.json. (Sorry, I forgot it !)
Minor refactoring.
Made doors depth-sorted + reworked collisions.
Working on boss level. Did a lot of refactoring.

For records, here is the list of the modifications, except the code for the boss level:
* Added Dagfin.hasObject to check if an object is in the inventory. (Should add addObject too).
* Moved objects and doors loading from GameState.update() to Level.parseLevel().
* Moved ownership of objects and doors lists to Level.
* Modified displayMessage to allow to specify callback's context.
* Modified the hitbox of doods (Player and Zombies) to approximatly fit their shadows.
* Modified the code of Dood.facingPosition() to produce a point closer from the dood and correctly aligned.
* Modified triggers callbacks to be Phaser.Signal. This allows to have several context and to specify their callbacks.
* Added an onActivate callback to objects and the code that trigger it in provessTriggers.
* Removed a few console.log.
* Did far too much modifications for a single commit.
Finished boss level (still some rought edges) + callback context for messages.