Spell effect additions...

Kayen: Implemented SE_ArcheryDoubleAttack (Chance to do an extra archery attack)
Kayen: Implemented SE_ShieldEquipDmgMod (Increase damage in primary hand if shield equiped)
Kayen: Implemented SE_ShieldEquipHateMod (Increase hate generated if shield equiped)
Kayen: Implemented SE_TriggerOnAmountValue (Trigger spell if HP/Mana/End bellow X value or num pet on target)