* Replace udns with c-ares
* Get IO loop work
* Clean up
* Avoid initializing nameservers each query
* Add ARES_OPT_SERVERS
* Refine resolv_cancel
* Fix a memory leak
* Replace udns.h with ares.h
* Fix all inet_* fucntions
* Clean up
* Enable servers_ports when VERSION_MINOR >= 11
* Avoid ares_inet_XtoX
* Handle multipe nameservers correctly
* Use ares_set_servers for IPv4 and IPv6 mixed list
* Refine c-ares for udprelay
* Refine ares_set_servers()
* Refine the timer based on ares_timeout
* Avoid resolv_cancel
* Fix an issue of null pointer
* Fix another null pointer issue
* Refine the order of resolv_shutdown
* Fix the corrupted ev io