Add exit CLI command
Add exit CLI command

Performance results:
2016-11-02 18:50:46,889 - TestPerf - INFO - Test test_1_4M_tcp_sess_setup_rate
2016-11-02 18:51:48,531 - TestPerf - INFO - Average Rate 3507982
2016-11-02 18:51:48,532 - TestPerf - INFO - Test test_2_8M_tcp_sess_setup_rate
2016-11-02 18:53:24,595 - TestPerf - INFO - Average Rate 3499332
2016-11-02 18:53:24,595 - TestPerf - INFO - Test test_3_10M_tcp_sess_setup_rate
2016-11-02 18:55:16,759 - TestPerf - INFO - Average Rate 3499471
2016-11-02 18:55:16,760 - TestPerf - INFO - Test test_4_4M_tcp_sess_data_10b_setup_rate
2016-11-02 18:56:26,353 - TestPerf - INFO - Average Rate 1840096
2016-11-02 18:56:26,353 - TestPerf - INFO - Test test_5_4M_tcp_sess_data_1024b_setup_rate
2016-11-02 18:57:35,984 - TestPerf - INFO - Average Rate 1827237
2016-11-02 18:57:35,984 - TestPerf - INFO - Test test_6_4M_tcp_sess_data_1300b_setup_rate
2016-11-02 18:58:45,630 - TestPerf - INFO - Average Rate 1974193
2016-11-02 18:58:45,630 - TestPerf - INFO - Test test_7_4M_udp_sess_data_10b_setup_rate
2016-11-02 18:59:38,834 - TestPerf - INFO - Average Rate 7433184
2016-11-02 18:59:38,835 - TestPerf - INFO - Test test_8_4M_http_sess_data_10b_setup_rate
2016-11-02 19:00:48,428 - TestPerf - INFO - Average Rate 1800710
jlijian3/warp17,jlijian3/warp17,jlijian3/warp17,jlijian3/warp17,jlijian3/warp17