Releases of vhd-format.0.7.0 and vhd-tool.0.7.0

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
mirage-types.1.1.0 and cohttp.0.9.15 needed

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Update to vhd-tool.0.7.1, which depends on nbd.1.0.1

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
vhd-tool needs nbd >= 1.0.1

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Add nbd.1.0.1 (already merged upstream)

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #15 from djs55/vhd

Releases of vhd-format.0.7.0 and vhd-tool.0.7.0