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

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

[coverage] main.py tests

[Windows] Fix quotes under windows

Improvement of the GTPv1 support.

A new test that triggers the bug (with ARPSourceMACField) has been added.

[coverage]  AS resolvers tests

Fix IPv6 support on Windows

EAP_MD5 class added.

Updates the CDP module (scapy/contrib/cdp.py).

We added:
- the update messages (GTPUpdatePDPContextRequest and
	GTPUpdatePDPContextResponse)
- several Information Elements (IE)
- few tests

Fix empty LLTDAttribute build & dissect

  - LLTDAttribute() produces a Raw instance (or crashes, when
    conf.debug_dissector is set).

  - str(LLTDAttribute(type=18)) crashes.

New defrag() test

Test send / sendp and sniff