The QDnsLookup class provides asynchronous APIs for performing
DNS lookups. For now, the following lookups are supported:
- A and AAAA
- CNAME as defined per RFC 1035
- MX as defined per RFC 1035
- NS as defined per RFC 1035
- PTR as defined per RFC 1035
- SRV as defined per RFC 2782
- TXT as defined per RFC 1035
Task-number: QTBUG-10481
Change-Id: I46c1741ec23615863eeca3a1231d5e3f8942495e
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>