Add forked Maatkit tools in bin/ and their tests in t/.

t/pt-visual-explain/samples/rental_index_merge_intersect.sql

@@ -0,0 +1,15 @@
+mysql> explain select * from sakila.rental where customer_id = 130 and inventory_id = 3009\G
+*************************** 1. row ***************************
+           id: 1
+  select_type: SIMPLE
+        table: rental
+         type: index_merge
+possible_keys: idx_fk_inventory_id,idx_fk_customer_id
+          key: idx_fk_inventory_id,idx_fk_customer_id
+      key_len: 3,2
+          ref: NULL
+         rows: 1
+        Extra: Using intersect(idx_fk_inventory_id,idx_fk_customer_id); Using where
+1 row in set (0.00 sec)
+
+mysql> notee