Add support for a loopback Vchan module, to satisfy the Conduit functor
Add a `VCHAN_xen` module that maps a working vchan implementation
CONSOLE is now a FLOW

This is a backwards-incompatible change which affects the following
CONSOLE functions:

  write
  write_all

Client applications need to be updated to use the new Cstruct.t based
blocking 'write' function:

  val write : flow -> buffer -> [`Ok of unit | `Eof | `Error of error ]
io

There is no non-blocking 'write' function. I believe lossy console
output functions are a mistake because they cause confusion when
debugging.

This is part of [mirage/mirage#203]

Signed-off-by: David Scott <dave.scott@citrix.com>
Merge pull request #302 from djs55/console-flow

CONSOLE is now a FLOW
Switch to using the unified mirage-console.2.0.0 package

See mirage/mirage-dev#26 for the new package
Merge pull request #304 from avsm/unified-mirage-console

Switch to using the unified mirage-console.2.0.0 package
Alias Console to Console_unix and Console_xen

This follows the changes in mirage/mirage-console#26
Merge pull request #305 from avsm/master

Alias Console to Console_unix and Console_xen
Merge pull request #300 from avsm/vchan-conduit

Add Vchan support to Mirage config.ml
Correctly show config file locations when using a custom one
Intall libxen-dev in Travis CI scripts
Merge pull request #310 from samoht/fix-travis

Intall libxen-dev in Travis CI scripts
Fix the generation of foreign modules (which are not a functor)
Merge pull request #293 from samoht/modules

Fix the generation of foreign modules (which are not a functor)
Update CHANGES
Merge branch 'master' of github.com:mirage/mirage

Conflicts:
	CHANGES
Merge pull request #314 from avsm/master

Correctly show config file locations when using a custom one
Plumb through Vchan peer UUID registration so that nodes can have names

This permits each configuration Conduit to specify a name for its
local node, which is subsequently used in Vchan lookups
Travis: Add a temporary shim in to build via avsm/ocaml-conduit
Travis: use opam 1.2.0