Merge pull request #19 from avsm/master

OCamldoc
Check for existence of /conduit in Xenstore for vchan coordination

Start adding scaffolding for .install generation
Add PEER.exists to make it easier to check for the validity of a name
update constraint on ipaddr to >=2.5.0 for sexp accessors
Merge branch 'master' of github.com:mirage/ocaml-conduit
Merge branch 'vchan-pure-build'
Lift out much of the resolver logic into a structure more suitable for Vchan

Specifically, vchan doesnt have a listen call as sockets do, so we need
to move to a Conduit-based solution for that.  Resolvers now register
vchan uuids to publish them in the namespace upon startup
Merge branch 'master' of github.com:avsm/ocaml-conduit
Merge branch 'master' into gh-pages
sync ocamldoc