Convert KDrive to GPE/GKE interface.
Add first-class drivers and enumerate every device separately through
Xi, instead of lamely attempting to aggregate them.
Add XKB support to the Linux keyboard driver.
Add 'thumb button' support to the tslib driver.
Rejig InitInput, so each DDX has to add a list of drivers it supports.
Support NewInputDeviceRequest, et al.
When COMPOSITE is enabled, call CopyWindow even when the pixels "don't
move" on screen.
Don't reject modes that are not supported by the unused monitor.
