Fix resolution reporting

Write to xenstore "[Width] [Height]" instead of "[Width] [Width]".
Note: I don't know how to compile the Windows tools so I did not test that fix, just noticed the issue on a test machine and found what I expected in the code.
Fix xenstore path for resolution reporting...

Ahem... The input server seems to expect a "desktopDimensions" (with an "s" at the end) node.
See https://github.com/OpenXT/input/blob/master/domains.c#L806
Merge pull request #1 from jean-edouard/master

Thanks Je