Bump to 2.0.0 and depend on Console_unix/Console_xen

See mirage/mirage#26 for details
Merge pull request #73 from avsm/master

Bump to 2.0.0 and depend on Console_unix/Console_xen
Add icmp6 error packet detection routine
Update OPAM dependency on mirage-console-unix to just mirage-console
Merge pull request #74 from talex5/fix-deps

Update OPAM dependency on mirage-console-unix to just mirage-console
Merge remote-tracking branch 'upstream/master'

Conflicts:
	lib/META
	setup.ml
Allocate packet right away, delay filling dmac
Fix sending of ICMP6 error packets
Initiate DAD for new IPs
Add DAD periodic handling

This takes care of cycling address stage PREFERRED -> DEPRECATED and of
timing out/resending DAD requests.