Add atomic load/store bindings for ring counters.

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #52 from djs55/forupstream/atomic-load-store

Add atomic load/store bindings for ring counters.
Exposed memory barriers in the Xenctrl module.
Merge pull request #53 from vbmithr/master

Exposed memory barriers in the Xenctrl module.
Adapted Mirage to the unified xenstore.

Conflicts:
	xen/lib/netif.ml
Fixed compilation.
Exposed the XenStore transport over Mirage.
Added Xenctrl in the mlpack.
Added atomic_stubs.c for gcc's atomic primitives.
Manage MAC addresses with ocaml-ipaddr.
Now we depend on ipaddr.
atomic_stubs.c are now safe.
Merge pull request #55 from vbmithr/new-xs-2

Adapted to the new ocaml-xenstore + some C bindings necessary for vchan.
Fix compilation with new ocaml-tuntap.
Update to 0.9.4
[xen] Port Netif to use the `Macaddr` module from `ocaml-ipaddr`.
Unhook `mir-run` from the build, as Mirari replaces it.
bump to 0.9.5 and correct deps in META files
Add a simple regression runner that builds the entire combination
of supported libraries.  It needs to be edited to set the variables
at the top to the correct pins (which can be blank)
sync CHANGES