Grenades: small standardization and mob sprite updates.

Made a new proc for grenades, update_mob(), it will be called in all the different prime() procs. This will drop the grenade of a mob and update his sprite, using the proper inventory proc. It will be only triggered if the loc is a mob.
Standardized all the grenades files
Grenades will no longer make you drop your items when they are triggered if you activated them.