CBQE-0: systests - generate a final report

added new param:
  -f JSON_TEST_FILE, --json_test_file=JSON_TEST_FILE
                        json test file; required

index.html file is generated as a final report

Change-Id: I3eaab4d6827aafbb1c28126cd96b915c1923c52a
Reviewed-on: http://review.couchbase.org/27979
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Andrei Baranouski <andrei.baranouski@gmail.com>