[ANN] packetgen 2.7.0 released

packetgen 2.7.0 has been released.

* home: <https://github.com/sdaubert/packetgen>
* bugs: <https://github.com/sdaubert/packetgen/issues>
* doc: <https://github.com/sdaubert/packetgen/wiki>

PacketGen provides simple ways to generate, send and capture network
packets.

Known protocols are: Ethernet, Dot11, Dot1x, ARP, IP, IPv6, GRE, ICMP,
IGMP, ICMPv6, MLD, MLDv2, OSPFv2, OSPFv3, UDP, TCP, SNMP, ESP, DNS, IKE,
EAP, BOOTP, DHCP, TFTP, NetBIOS, HTTP and MDNS.

Changes:

### 2.7.0 / 2018-08-29

* Add Header.list as an alias to Header.all.
* Add Packet#reply and Packet#reply! to generate (or modify, resp.) a
packet with all its invertible fields inverted to make a response.
* Introduce a new bind API to customize packetgen. This bind API is used
to add new recognized headers.
* Deprecations:
* deprecate all methods named #has_<attr>? in favor of #<attr>?.
* deprecate Header::Base.bind_header in favor of the more consistent
new API: Header::Base.bind.
* Fix bugs:
* When a packet was dup'd, headers was so, but not magic accessors
to them. This is now the case.
* When a header was dup'd, it was not deeply duplicate, and a change
done on a field on dup'd header also modified initial header. This is
now fixed by deeply duplicate headers and fields.
* Types::Array no more inherits from Array. This should fix some
minor issues.