GM Island mailbox fix

The fixes the GM Island mailbox, which up to this point was only usable
by Alliance.

Fix Author: Elarose
Stormgarde Troll Hunter cast spell fix

This fixes the "NULL target for ACTION_T_CAST creature entry 2583
casting spell id 2767" error, for the Stormgarde Troll Hunters.
The target field (parameter 2 of action 1) was 1, when it should have
been 0
Gnarlpine Totemic cast heal on self fix

This fixes the issue where the Gnarlpine Totemic is casting heal on the
player instead of itself
The target field (parameter 2 of action 1) was 0 (target is the creature
it is attacking), when it should have been 1 (target is itself)
Cluck quest fix

The fixes the Cluck! quest, where the Continue button is disabled when
it should be enabled -
SpecialFlags field in quest_template table should be set to 0, not 1
Quest 5381 not completable (chance of item spawn -100%)

This fixes the issue where the Quest 5381 Hand of Iruxos is not
completable, due to the demon box not appearing as loot after killing
the
NPC (after breaking the crystal with the pickaxe)

The spawn chance for the demon box in the creature_loot_table was set to
-100 (minus 100 percent)
Misha the bear Rexxar's buddy

Misha will now join Rexxar on his travels
Merge pull request #160 from Chuck5ta/Rel20

GM Island mailbox fix