Change NPCs to have their attack delay set in DB

This gives us a much more straight forward way of setting mob
attack delay with respect to live.

The attack_delay column is in 10ths of seconds, just like weapons are
The attack_speed is left for references for now.

utils/sql/git/required/2014_09_09_attack_delay.sql

@@ -0,0 +1,3 @@
+ALTER TABLE `npc_types` ADD `attack_delay` TINYINT(3) UNSIGNED DEFAULT '30' NOT NULL AFTER `attack_speed`;
+UPDATE `npc_types` SET `attack_delay` = 36 + 36 * (`attack_speed` / 100);
+UPDATE `npc_types` SET `attack_delay` = 30 WHERE `attack_speed` = 0;