Ptr (#30)
Ptr (#30)

* 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

* adding PTR support

* validate IP addresses passed in for PTR lookup

* define err this time

zmap/zdns,zmap/zdns,zmap/zdns