Fixed bug on hole clearer trial

 * Changed the separator:on_activated on a separator:on_activating
 * fix #6 via christopho/solarus@9250396b8f369e4fe9e08f2b800a2a6e768b0807
 * fixed torches bug if multiple fire collision or if re-enter the room
after exit it
 * Hole eater is now disabled if the trial is completed
 * Fixed a bug with hole_eater_launcher not disabled when torch was unlit,
so the hero could walk on the holes
Changed the teletransporter of weaponry

With the new setters and getters of the teletransporter api, only one
teletransporter is needed for the weaponry, which redirect to the good map
at start.