* apply StackIP changes and internet package test passing
* fix tests and examples
* remove old Reset method on StackIP
* use encapsulate for ipv6
* add TCP over IPv6 tests
* begin adding icmp client
* rely on anon structs
* add tests
* tests passing
* icmp fleshed out
* rework icmp to include ip addr
* rename StackAsync.Demux/Encapsulate to RecvEthernet and SendEthernet
* remove legacy unreachable TCP tests
* remove uses of deprecated internet.StackNode in preference of lneto.StackNode
* documentation
* rename methods to signal no I/O happening
* improvements to dhcpv4 server
* begin adding examples/httpserver
* add better VLAN tagging methods
* pcap: add error printing; fix bug in CRC
* ipv4: ToS and Flags construction and flag manipulation improvements
* add dhcp interception to httptap and improve httpserver example