Remove BOM from 2013_05_21_00_world_trinity_strings.sql

Remove UTF-8 BOM (byte order mark) encoding and specifically set to UTF-8 without BOM. BOM artifacts prevent queries from running via CLI.

``You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'ï»¿DELETE FROM `trinity_string` WHERE entry IN (453, 548, 549, 550, 714, 716, 74' at line 1
``