[0768] Fixed quest 2518 prerequist

* Fixed quest 2518 (Tears of the Moon) which was having another quest as prerequist while it does not have one
this closes #620
Source: http://www.wowwiki.com/Quest:The_Temple_of_the_Moon

Signed-off-by: Cala <calaftp@free.fr>
[0769] Added missing equipment for creature 14221

* Added missing equipment for creature 14221 (Gravis Slipknot)
Thanks Scotty0100 for pointing and @beach-creature for providing the
right values. This closes #615
[0770] Fixed position of NPCs 3880 & 3901 in Ashenvale

* Fixed position of NPC 3880 (Sentinel Frostshadow) and 3901 (Illiyana)
in Ashenvale because they were located in Forest Song and were located
elsewhere back in Classic
Thanks Zingzah for pointing. This closes #621