vhd-format.0.7.1 and vhd-tool.0.7.5

Signed-off-by: David Scott <dave.scott@citrix.com>
Merge pull request #2311 from djs55/vhd

vhd-format.0.7.1 and vhd-tool.0.7.5
Merge pull request #2321 from avsm/master

+uri.1.7.1
+cstruct.1.3.0