NTP : update and small fixes

Create a secdev team in AppVeyor

[rewritten] PR #182

[coverage] Tests for ManufDB + Multiple fixes

[Pickling] Add packets pickling support

coap: allow CoAP packets to have a payload

https://datatracker.ietf.org/doc/draft-ietf-6man-segment-routing-header/?include_text=1

From PR #182

[Windows] Fixed VBS fallback

[General] Doc improvements + mercurial logs removed 

dot11 ack frame dissection

[coverage] Better unit tests for inet6.py

Flags: allow operations (| & ==) with strings

[coverage] Speed up all tests x2

[Tests] Fix AS_RESOLVER

Improve TCP.answers()

Without this code, when an out of connection TCP packet receives a
TCP answer with flag RST and the ack set to 0, it is not seen as an
answer.

This comes without regression tests because I have been unable to
find a reliable machine without firewall on the Internet.

Simple test, if 192.168.0.1 has no firewall:

>>> sr(IP(dst="192.168.0.1")/TCP(sport=80, dport=12345, flags='SA'),
...    timeout=2)

This test will not terminate without this patch.