Only react on the last Expose event in a series of events. (#2636)

Thanks to @psychon for pointing this out during the review of PR #2624.
This commit extends this change to all other occurences of Expose events
within i3.

src/handlers.c

@@ -1511,7 +1511,10 @@ void handle_event(int type, xcb_generic_event_t *event) {
             break;
 
         case XCB_EXPOSE:
-            handle_expose_event((xcb_expose_event_t *)event);
+            if (((xcb_expose_event_t *)event)->count == 0) {
+                handle_expose_event((xcb_expose_event_t *)event);
+            }
+
             break;
 
         case XCB_MOTION_NOTIFY:

src/restore_layout.c

@@ -360,7 +360,10 @@ static void configure_notify(xcb_configure_notify_event_t *event) {
 static void restore_handle_event(int type, xcb_generic_event_t *event) {
     switch (type) {
         case XCB_EXPOSE:
-            expose_event((xcb_expose_event_t *)event);
+            if (((xcb_expose_event_t *)event)->count == 0) {
+                expose_event((xcb_expose_event_t *)event);
+            }
+
             break;
         case XCB_CONFIGURE_NOTIFY:
             configure_notify((xcb_configure_notify_event_t *)event);