enable RDP after installation

Need to open the right port in the firewall, and to turn on remote desktop
(terminal services) in the registry
forward SSH port, as it isn't by default on Windows
vagrant-windows is not needed now that 1.6 required
Merge branch 'forward-ssh-port' into with-volume-key
Merge branch 'enable-rdp' into with-volume-key
trim back some space used by software updates
clarify readme about updates
Merge branch 'clean-software-updates' into with-volume-key