bug fixes
1. function iszero if s = "     1", len = 6, isaero return 1,The result is wrong
2.in function process_cache_dns if val->flags = 1 val->down = NULL queue_join_init(q, NULL)->core dump
3.in function queue_join_init if q1-head = NULL is not clear when the q2
4.in function setfilename if url is longer than sizeof(info->fi.filename) overflow