MaNGOS merge: Mail System.

* Store loot in mail_loot_template indexed by mail template ids.
* Implement proper creating mail text copy item from mail template based mail.
* Move send functions to new MailDraft class from WorldSession.
* Implement mails sending at player levelup.
* Autor VladimirMangos, converted by me.

--HG--
branch : trunk

sql/updates/6521_world_command.sql

@@ -0,0 +1 @@
+UPDATE `command` SET `name`='reload mail_loot_template' WHERE `name`='reload quest_mail_loot_template';