Mirage release milestone

[Anil Madhavapeddy <anil@xxxxxxxxxx>]

We have made great progress in benchmarking and understanding the performance
characteristics of Mirage kernels in the past few months.  It's now time to
cut a reasonably stable alpha release to act as a base for future work. Luckily,
not a huge amount of work is needed for this!

I've created a 0.2-alpha milestone in Github:
https://github.com/avsm/mirage/issues?milestone=3&state=open

The three main issues are:

Convert to Bigarray I/O exclusively:
https://github.com/avsm/mirage/issues/93

Disaggregate the giant monolithic repository:
https://github.com/avsm/mirage/issues/95

Convert Bitstring into a C-like 'struct' camlp4 extension:
https://github.com/avsm/mirage/issues/94

I can't figure out how to CC Github issue traffic to this list (or even
if we should), but I'll update those issues with progress as I work through
them. None of these are particularly chunky bits of work, but they touch the
whole repository and so should be complete before we release any code.

Comments (or other things anyone would like to do before the 0.2 alpha) are
welcome. In particular, Amir's Jenkins setup should be integrated, so that
we have performance regression tests, so help on that front (both writing
tests and the Jenkins integration) would be welcome. 

Also
Thomas: your thoughts on #95 and OPAM integration
Dave: figuring out the OS.Xen/OS.Unix portion of #95 (with respect to the 
user-space blkback ring patches, configure scripts, and all that stuff)

-anil