Fix typo in tests

Fix 64 bits architectures detection

Retry .whois() test on failure

* Fix IA_PD length error

I tested this and noticed wireshark wasn't parsing the message correctly. Turns out the length is wrong.

* Update regression.uts

Fix test for DHCP6OptIA_PD

* Update length of DHCP6OptIA_PD in test.

Contrib gtp v2

Introduce FlagValue() objects to represent FlagsField() values

This PR makes it possible to check if several flags are all set, by
writting, for example, `if pkt[TCP].flags.SA:`.

It only works for single letter flags (e.g., will work for TCP().flags
but not for IP().flags), and only when getting a value.

Thanks @guedou for suggesting that.

It is now possible to write `pkt[TCP].flags.S = True`.

This makes it possible to write `if pkt[TCP].flags.S: [...]`.

[coverage] More unit tests for scapy/*.py files

[DOCS] Installation + Links fixed (Windows)

Make SourceIPField() .i2m() and i2h() methods consistent

[coverage] VRRP, L2TP, HSRP, RIP, & Radius tests

[coverage] main.py tests