Core/Scripts: triple zone cleanup

Remove hardcoded (as well as deprecated) text in the following places:
- blackrock_depths.cpp
- zone_burning_steppes.cpp
- zone_stormwind_city.cpp

Updates https://github.com/velinath/TrinityCore/issues/2

sql/updates/world/2016_02_28_CLEAN-UP_world.sql

@@ -0,0 +1,2 @@
+-- remove script from core requires removing ScriptName from creature_template
+UPDATE `creature_template` SET `ScriptName`= '' WHERE `entry`IN (1749,2708);