All items are now properly created, copied and destroyed.
  (too much copying - should avoid in later development)

Modified API of dns-simple 'library':
  Added destructors which take ** to the object
    and are setting the pointer to NULL.
  dnss_dname_to_wire() now takes the position and allocated size as parameters.
  dnss_create_response(), dnss_create_error_response() and dnss_wire_format()
    now all return errors as appropriate.

Fixed copying issues in dns-simple 'library':
  Questions and RRs are now copied entirely, not just pointers.
    (See functions dnss_copy_questions() and dnss_copy_rrs().)
  Added some checks for NULL-pointers when deallocating.

Added pointer to hash table item destructor function to the hash table.

ck_destroy_table() rewritten to destroy individual items in the table and buffer.

A lot of checks added (mostly for result of malloc).

Redundant and old code removed.