Set newxp/newyp when creating player

This fixes a bug where the player's y-position would be incorrect if
they loaded a save that was on a conveyor and it was their first time
loading in since the game was opened.

This is because on the first load, the game creates a new player entity,
but on subsequent loads, the game re-uses the player entity. Subsequent
loads use mapclass::resetplayer(), which already has the newxp/newyp
fix, but as for the first time, the game does not set newxp/newyp.

So just set newxp/newyp, like in mapclass::resetplayer().

desktop_version/src/Entity.cpp

@@ -1273,6 +1273,10 @@ void entityclass::createentity(int xp, int yp, int t, int meta1, int meta2, int
         entity.h = 21;
         entity.dir = 1;
 
+        /* Fix wrong y-position if spawning in on conveyor */
+        entity.newxp = xp;
+        entity.newyp = yp;
+
         if (meta1 == 1) entity.invis = true;
 
         entity.gravity = true;