Add support for the spice tablet interface. The tablet interface will
be registered (and then used by the spice client) as soon as a absolute
pointing device is available and used by the guest, i.e. you'll have to
configure your guest with '-usbdevice tablet'.
Open keyboard channel. Now you can type into the spice client and the
keyboard events are sent to your guest. You'll need some other display
like vnc to actually see the guest responding to them though.