vhddisk: add dependency on mirage-unix: vhddisk is userspace only

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
xen-block-driver: configure script needs Cmdliner
xen-block-driver: use 'make' rather than '"make"'
xen-block-driver: add configure step
xenctrl: configure is run by the Makefile now

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
xen-block-driver: Makefile calls configure

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Remove vhddisk (renamed to xen-disk in mirage/) and xen-block-driver (released 0.2.0)
Add a temporary initial snapshot release of the vhd parsing/printing library (will be called 'vhd-format')
'vhd' renamed to 'vhd-format'
Add vhd-format.0.0.2 (with ocamlfind package vhd-format)
We don't need the "development" version of vhd-format any more

Developers should use pin, and make new releases regularly...