Remove BOM from 2013_05_21_00_world_trinity_strings.sql

Convert to UTF-8 without BOM (byte order mark). BOM prevents query from executing in 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 (45548, 549, 550, 714, 716, 74' at line 1
``