* 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
* pcap: reuse Frame memory
* slog: reduce heap allocations of addresses; also prevent heap alloc of dhcp options in pcap
* dns: heapless improvement; add StackAsync buffer for more heapless operation; start thinking of errors
* errors: begin standardise errors in lneto
* errors: finish standardization of errors
* fix merge issues
* add more lneto errors to rest of package
* format errors.go
Pat Whittingslow