* add mdns
* define mdns.Client
* fix some mdns stuff
* refine dns package for use with mdns
* remove Querier and Responder and replace with Client
* add record setting methods on dns.record to reuse record buffer
* protect against unbounded client answer growth
* round off sharp mdns edges; reduce allocs
* add mutlicast to stacks; add xnet tests for mdns
* fix documentation on acceptmulticast field
* mdns working
* work on tracking more heap allocations down
* write own heapless IP AppendFormatAddr functions
* remove potential Error method allocations
* more logging
* 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
Pat Whittingslow