[12507] Implement proc effect of spells 67712, 67758

related to items 47316, 47477.

Signed-off-by: Schmoozerd <schmoozerd@cmangos.net>
[12508] Fix SpellDamage modifier of SPELL_AURA_MOD_DAMAGE_DONE_CREATURE

This aura modifies a flat value, not a percent value.

Related cmangos/cmangos-classic#26

Signed-off-by: Schmoozerd <schmoozerd@cmangos.net>
[12509] Check cast spell 51690

Signed-off-by: Schmoozerd <schmoozerd@cmangos.net>