Change dependency 'vhd' to 'vhd-format'.

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Update to 1.0.1

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #1 from djs55/master

Change 'vhd' dependency to 'vhd-format'