Add ESCLocation node (#323)

Fixes #306

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

@@ -0,0 +1,37 @@
+# A simple node extending Position2D with a global ID so that it can be
+# referenced in ESC Scripts.
+extends Position2D
+class_name ESCLocation
+
+# The global ID of this item
+export(String) var global_id
+
+# If true, player orients towards 'interaction_direction' as
+# player character arrives.
+export(bool) var player_orients_on_arrival = true
+
+# Let the player turn to this direction when the player arrives 
+# at the item
+export(int) var interaction_direction
+
+
+# Used by "is" keyword to check whether a node's class_name
+# is the same as p_classname.
+#
+# ## Parameters
+#
+# p_classname: String class to compare against
+func is_class(p_classname: String) -> bool:
+	return p_classname == "ESCLocation"
+
+
+# Ready function
+func _ready():
+	if not self.global_id.empty():
+		escoria.object_manager.register_object(
+			ESCObject.new(
+				self.global_id,
+				self
+			),
+			true
+		)