reassembly: fix check overlap for case 6

Fix Fatal->Fatalf in reassembly example.

Merge pull request google#649 from Lightspeed-Systems/dnsencodeblankq

Proper size calculation for encoded question name

Add minimum go version requirement to documentation.

This fixes google#479

add icmpv6 echo serialize function

fix nfds error in select statement

From man page for select "nfds should be set to the highest-numbered
file descriptor in any of the three sets, plus 1". This was causing
one of our apps to never capture packets as the fd returned by
pcap_get_selectable_fd was 8 and then never checked.

Release 20170808

Guard a second instance of pcap_compile.

Merge pull request google#119 from randstr/ip6-review

Add LayerGoString() to packet.go

Add Bill Green to AUTHORS.