Keyboard map notifications are always generated from within XKB code,
which also takes care of copying the keysyms, etc.  If you need to
mangle the keymap yourself, generate a new core keymap/modmap, and pass
it to XkbApplyMappingChange.

SendMappingNotify is renamed to SendPointerMappingNotify (and ditto its
Device variants), which still only _sends_ the notifications, as opposed
to also doing the copying a la XkbApplyMappingChange.

Also have the modmap change code traverse the device hierachy, rather
than just going off the core keyboard.

Signed-off-by: Daniel Stone <daniel@fooishbar.org>