[4.3.4] Spells/Mage: Mirror Image summoning

Fixes the summonig of Mirror Images npcs and implements the Glyph of Mirror Image.

Mirror Image: http://old.wowhead.com/spell=55342
Glyph of Mirror Image: http://old.wowhead.com/spell=63093

Anyways the AI seems to still bugged by some reason (at least on my case).