modules/world: add a function to add Actor from index

gamecore/modules/world/baseworld.lua

@@ -20,6 +20,10 @@ end
 -- ACTOR MANAGEMENT FUNCTIONS
 -- Basic function to handle actors
 
+function BaseWorld:newActor(name, x, y)
+  self.obj.index[name](self, x, y)
+end
+
 function BaseWorld:registerActor(actor)
   table.insert(self.actors, actor)
 end