Update pcap-dos.c

* Receive-buffer is now calloc'd inside pcap_t. 
* Improved 'p->break_loop' handling. 
* Corrected netmask values in pcap_lookupnet().
* The find-all function is now called pcap_findalldevs_interfaces().
* A PktDrvr has no address but use the AF_INET just the same.