fix: prevents duplicate item registration (#587)

* fix: prevents duplicate item registration and also ensures that the player is forcibly registered
* updates ESCLocation to respect duplicate registration rules

addons/escoria-core/game/core-scripts/esc_item.gd

@@ -168,6 +168,9 @@ var _movable: ESCMovable = null
 # The identified animation player
 var _animation_player: ESCAnimationPlayer = null
 
+# Whether to force regsitration with the object manager. Defaults to false.
+var _force_registration: bool = false
+
 
 # Add the movable node, connect signals, detect child nodes
 # and register this item
@@ -210,7 +213,7 @@ func _ready():
 				self
 			),
 			null,
-			true
+			_force_registration
 		)
 
 		terrain = escoria.room_terrain

addons/escoria-core/game/core-scripts/esc_location.gd

@@ -39,7 +39,5 @@ func _ready():
 			ESCObject.new(
 				self.global_id,
 				self
-			),
-			null,
-			true
+			)
 		)

addons/escoria-core/game/core-scripts/esc_player.gd

@@ -13,6 +13,7 @@ export(bool) var selectable = false
 # A player is always movable
 func _init():
 	is_movable = true
+	_force_registration = true
 
 
 # Ready function