Added parsing of SNF_FLAGS, packet injection, snf_findalldevs for SNF API

Bug Fixes so --with-pcap=snf builds properly
Added back in EBUSY as it can be returned in SNFv3 by snf_ring_recv().
using the PACKET_COUNT_IS_UNLIMITED() macro
using the PACKET_COUNT_IS_UNLIMITED() macro
Merge pull request #375 from myri/master

Added parsing of SNF_FLAGS, packet injection, snf_findalldevs for SNF API