I believe the following is correct (tested on beta last night) but feel free to double-check me on it. The important spells are:

• Expunge (365585) - Poison dispel
• Naturalize (360823) - Magic/Poison dispel (always both since Preservation Evokers get Expunge for free)
• Cauterizing Flame (374251) - Bleed, Poison, Disease, and Curse dispel

elseif class == 'EVOKER' then
			func = function()
				dispel.Magic   = IsPlayerSpell(360823)
				dispel.Curse   = IsPlayerSpell(374251)
				dispel.Poison  = IsPlayerSpell(360823) or IsPlayerSpell(365585)
				dispel.Disease = IsPlayerSpell(374251)
			end