[ANN] packetgen 2.8.4 released

packetgen 2.8.4 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.

Supported 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:

### 2.8.4 / 2018-10-02

* Add Types::Fields.update_field and .remove_bit_fields_onto to ease
defining new headers by inheritance.
* Deprecate Types::Fields#delete_field in favor of #remove_field
* Fix 2 bugs in Utils module:
  * Utils.arp_spoof did not work due to a change in parameter name in
Utils::ARPSpoofer#initialize.
  * Utils.mitm : sending packets at IP level no more work. Now, sending
them at Eth/Dot11 level.

### 2.8.3 / 2018-09-26

* Add sign integer types in Types module.
* Types::Fields.define_field: default option may now take a lambda
* Deprecate Types::Fields#is_optional? and #is_present?.
* Types::Fields.delete_field now undef magic field methods.
* lighten inspec output for headers.
* Add Types::Fields#bits_on to get bit definitions (if any) for given field.

### 2.8.2 / cancelled

### 2.8.1 / 2018-09-16

* Types::IntString#to_human: does not #inspect string, as #to_human
never does this for all others types.
* Fix 2 bugs:
  * Types::CString and Types::IntString: add #from_human to ensure such
a field may be set by Packet#add.