This commit updates kdig's check_reply_question() function so that it
compares the original wire format QNAME of the query against the
original wire format QNAME of the response. Using knot_pkt_qname()
instead of knot_pkt_wire_qname() only compares the downcased QNAMEs.

RFC 5452:

    4.2.  Matching the Question Section

       DNS packets, both queries and responses, contain a question section.
       Incoming responses should be verified to have a question section that
       is equivalent to that of the outgoing query.

I think "equivalent" here means that the case of the QNAMEs should be
compared too.

This commit adds a new function knot_pkt_wire_qname() that returns the
QNAME in the wire format buffer. This is implemented the same as the
original knot_pkt_qname() function before this branch, but now that we
no longer modify the QNAME in the wire format buffer in-place, this
should now be the "original" QNAME as seen off the wire (if the packet
was parsed from a socket buffer).

This commit makes knot_pkt_qname() return a const pointer to indicate to
callers that the contents (the QNAME in the wire format buffer) should
not be modified.

This reverts commit 4a3eb76b.

This reverts commit 55663f09.

This reverts commit 7f3aa3f6.

kdig: allow trailing data in XFR and preserve dname letter case in XFR

See merge request !1409

kzonesign: implemented zone verify

See merge request !1199

Geoip checks

Closes #778

See merge request !1407

Rrsig-refresh2

See merge request !1404

tests: fail if some test segfaults or killed

See merge request !1406