xinput2 ffi definitions
mask decoding errors in x-lookup-string fixme: handle properly
add partial support for XGenericEvents/XInput2
call XFree on string returned by XGetAtomName
add a handler for X errors so they don't kill the lisp
fix bug in xi-select-events
start work on querying/parsing connected device info

seems to be working to the point of printing things out, but
still need to return the data in some useful form
pass display to generic event dispatch, add constants for XI2 event #s
more event handlers, print info about added devices
make sure XIQueryVersion is available before calling it
try to move xinput2 specific init code out of xlib.lisp
test more XI2 stuff
more formatting cleanup
use :ON-FOO NIL in xinput test to match event handlers
add a continue restart around x11 generic event dispatch
more work on xinput2 stuff
handle XInput2 button events
send events when XI2 devices change
don't error on unknown XI2 device classes
don't error on unknown X11 keysyms