shift-click, control-click, and alt-click

[Robert Ringrose]

Problem solved.  It turns out that, although in the manual it states that
the keyboard is a special device which "reports an event only on a
downstroke, taking into account the <ctrl> and <shift> keys", you can still
read the status of the control, shift, and alt keys as buttons.

The catch is that you can still read them as buttons - they are defined in
device.h, so apparently (my) manual only gives a partial listing of the
defined buttons.

You can't check for shift-click as a single, queue-able event, but this
is close enough for what I need to do.

	- Robert
(Thanks to Andrew Myers and Lee Campbell for pointing me in the right
direction)

"There's always one more bu6."