More work on vcxproj builder.

Change-Id: Iac07ccda74b2afc796d8c1b415bdf49ca2c4d383
Reviewed-on: http://www.matthewh.me/gerrit/42
Reviewed-by: Matthew Hoggan <mehoggan@gmail.com>
Tested-by: Matthew Hoggan <mehoggan@gmail.com>