error in nle_processing fixed

nle_processing/sketch_NLE_CA/NLE_CA.pde

@@ -479,6 +479,8 @@ class NLE_CA extends CellularAutomaton {
 
   void do_move_group_NL(int label,int dir) { exit(); }
 
+  int count_N_neighbors(int bx,int by) { exit(); return 0; }
+
   boolean may_absorb(int bx,int by) { return is_filled_L(bx,by); }
   boolean may_desorb(int bx,int by) { return count_N_neighbors(bx,by) < minndes; }