Mxpref (#45)
Mxpref (#45)

* check if module allows access to stdin

* adding nslookup module

* librarifying out nslookup so that it can be called from axfr

* base AXFR working. still need to move around some field names

* spell miekg correctly

* reasonable error handling

* rdata -> data

* authors file in the wrong location

* adding MX preference to output for MX module

zmap/zdns,zmap/zdns,zmap/zdns