gamedatas:
[*] ClassicPlayer.java : added removeItem method, optimisation of the item system (still need some additions).
[*] Store : finished the method changing the number of Items in the store.
items:
[*] Item : optimisation, added useItem(ClassicPlayer) and dropItem(ClassicPlayer).
[*] Cam, Doc : updated to fir with the modifications of Item.
[-] ItemOnTheMap: not needed anymore.
[+] Gun, Knife : added some Items.
[+] EmptyItem : very useful.
Merge origin/JoachimW-M

Conflicts:
	src/gamedatas/ClassicPlayer.java