fix the froggy problem.

Implement a handler for the MappingEvent, meaning that the keymap has changed.
When this happens, ungrab all bindings, update the map, and regrab.

Fixes the problem where some keybindings wouldn't work under non us or
uk keymaps (especially the .fr map, it seems). Issue noticed by
ajacoutot@, ratchov@, and a few people on misc. Based on an initial diff
from ratchov@.

ok okan.

calmwm.c

@@ -101,6 +101,7 @@ main(int argc, char **argv)
 	XEV_QUICK(NULL, NULL, Expose, xev_handle_expose, NULL);
 	XEV_QUICK(NULL, NULL, DestroyNotify, xev_handle_destroynotify, NULL);
 	XEV_QUICK(NULL, NULL, ClientMessage, xev_handle_clientmessage, NULL);
+	XEV_QUICK(NULL, NULL, MappingNotify, xev_handle_mapping, NULL);
 
 	xev_loop();