I need to do SOA queries, so here is a parser for them.
- ares_soa_reply: new struct
- ares_malloc_data/ares_free_soa: ARES_DATATYPE_SOA_REPLY
- ares_parse_soa_reply: actual function
to return a linked lists of results. These were also modified to internally
use the ares_data memory struct and as such its result must be free'ed with
ares_free_data().