modules/world: automatize multiple character handling

gamecore/modules/world/baseworld.lua

@@ -144,6 +144,11 @@ end
 
 function BaseWorld:initPlayers()
   self.players = {}
+  self.playerNumber = 1
+end
+
+function BaseWorld:setPlayerNumber(playerNumber)
+  self.playerNumber = playerNumber or 1
 end
 
 function BaseWorld:addPlayer(actor, sourceid, haveCam)
@@ -214,8 +219,10 @@ function BaseWorld:loadMapPlayers()
       print("DEBUG: loading actors in player layer")
       local i = 1
         for k, object in pairs(objectlayer.objects) do
-          self:addPlayer(self.obj.Player(self, object.x, object.y), i, true)
+          if (i <= self.playerNumber) then
           -- TODO: don't hardcode camera handling
+            self:addPlayer(self.obj.Player(self, object.x, object.y), i, true)
+          end
           i = i + 1
         end
         self.map:removeLayer(objectlayer.name)