Quoted variables passed for do_sign

Spaces in variables may cause issue for certname and crossign path.
Quoted them for safety.

Addresses OpenXT/openxt#33
add missing targetname nodes
explicitly handle error propagation in foreach-object lopps since
powershell hides errors
Pass signtool path to doverifysign rather than assume signtool in
the path. To make this easier (since I don't know how to handle
arguments with spaces in CMD batch files), rewrite doverifysign in powershell.
Merge pull request #9 from pearsonk/master

Quoted variables passed for do_sign
Merge pull request #10 from dickon/master

A few fixes for the xc-windows build
disable OACR to prevent it leaving locks in the build tree
Merge pull request #11 from dickon/master

disable OACR to prevent it leaving locks in the build tree
Fix xenbus to cause surprise removals for vusb device on removal.

The Windows front end vusb driver expects to be removed via a
surprise removal. The existing code was trying to do an eject
which was not causing the front end driver to finish cleaning up
the device that was removed. Custom code for surprise removal was
only added for vusb devices to prevent injuring the already delicate
shutdown/removal code for other types of devices.

OXT-35

Signed-off-by: Ross Philipson ross.philipson@gmail.com