ANN: mirage.0.9.5 stream

[Anil Madhavapeddy <anil@xxxxxxxxxx>]

This fixes a number of usability and stability bugs, as well as moves out 
IP/MAC address parsing into a common library.  (In particular, the ring atomic 
load fix may well solve Dimos and Haris' problem with TCP performance -- could 
you try this?).

I've also added a `mir-rt` script that, when run, builds a fresh Mirage-www for 
all the supported variants (unix-direct, unix-socket and xen).  This helps keep 
all the various builds in sync, and will help with integrating kFreeBSD and 
Javascript backends when they're ready too. 
https://github.com/mirage/mirage-platform/blob/master/scripts/mir-rt

Mirage-Platform:
https://github.com/mirage/mirage-platform/releases/tag/v0.9.5
0.9.5 (09-Aug-2013):
* Add the `mir-rt` regression runner to `scripts/` (not installed).
* Unhook `mir-run` from the build, as Mirari replaces it.
* [xen] Port Netif to use the `Macaddr` module from `ocaml-ipaddr`.
0.9.4 (07-Aug-2013):
* [xen] add atomic load/store bindings for shared memory rings
* [xen] add atomic operations necessary for vchan
* [xen] expose memory barriers via Xenctrl ocamlfind package

Mirage-Net:
https://github.com/mirage/mirage-net/releases/tag/v0.9.4
0.9.4 (09-August-2013):
* Use the `Ipaddr` external library and remove the homebrew
  equivalents in `Nettypes`.

Mirari:
https://github.com/mirage/mirari/releases/tag/v0.9.7
0.9.7 (2013-08-09):
* Generate code that uses the `Ipaddr.V4` interface instead of `Nettypes`.

Shared Memory Ring:
https://github.com/mirage/shared-memory-ring/releases/tag/shared-memory-ring-0.4.1
* Read and update uint32_t shared ring counters atomically