ClientPoker.java:

- added sleep 2 sec before close the application

Memo:
- test on the Dealer.java about of getCombinationValue function
  Yesterday, the test below was wrong:
  1. Player Paul got a combination of [109,107] so double pair_combination
  2. Player Toto got a combination of [113] so pair_combination
  Player Paul must been the winner with a double pair against a simple pair
  but player Paul was the looser

  !!!! CORECT THIS ERROR !!!!