Merge pull request #2 from thomassa/io_nice_cp7327

CP-7327 nice and ionice config options for sparse_dd.conf
Merge pull request #4 from djs55/master

xapi-project:master catching up with upstream djs55:master
sparse_dd: Fix references to Vhd_lwt.File.use_unbuffered

Signed-off-by: Euan Harris <euan.harris@citrix.com>
CHANGES: Update for 0.7.3

Signed-off-by: Euan Harris <euan.harris@citrix.com>
impl: Strip leading slash from filename if prefix is supplied

If prefix is supplied but does not include a trailing slash,
then the filename will have a leading slash which will cause
int_of_string to fail when trying to interpret the filename
as sequence number later.

Signed-off-by: Euan Harris <euan.harris@citrix.com>
Merge pull request #13 from euanh/master

vhd-tool fixes