VXLAN: more layer bindings

PR #725 improved

Add next_cls_cb attribute to PacketListField

* Fix warning texts not being printed

* Add legacy style + histfile

* Fix Doc, readme, appveyor

* Add packet fields auto-completion (thanks to @p-l-)

* Pickle, session, interact tests

* Remove trailing line

Replace TLS prints with logging

LLDP - support for basic TLVs according to: IEEE 802.1AB-2016

Fix DHCPv6 Relay message behavior

  - this feature adds the ability to have a PacketListField
    of heterogeneous Packet types with dynamic discovery
    of the next type. This discovery can be based on any elements
    including previously parsed packets, underlayers, remaining
    bytes (look ahead), and last parsed packet.
  - this feature also adds the ability to parse PacketListFields
    where neither the length nor the number of elements can be
    predicted before parsing. This could be done previously using
    a length_from callback that did significant peeks into the
    string to parse, but it felt clumsy.

Windows: remove confusing warning message (@gpotter2)

* Python3: fix set_promisc() with Linux

* Fix debug dissector error message

* Make run_scapy3 executable

[IPv6] Windows: fix IPv6 routing + Net6

In order to avoid any conflicts when the consts are changed

This will speed up the boot