There is no mirage-block (only mirage-block-{unix,xen})
Expose raw BLOCK devices

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
... and substitute page_aligned_buffer with Cstruct.t

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
xen blkfront is in mirage-block-xen.front

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #30 from djs55/there-is-no-mirage-block

There is no mirage-block (only mirage-block-{unix,xen})