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.

i3-input/main.c

@@ -525,7 +525,10 @@ int main(int argc, char *argv[]) {
                 break;
 
             case XCB_EXPOSE:
-                handle_expose(NULL, conn, (xcb_expose_event_t *)event);
+                if (((xcb_expose_event_t *)event)->count == 0) {
+                    handle_expose(NULL, conn, (xcb_expose_event_t *)event);
+                }
+
                 break;
         }