Shal'ille reagent/casting cost changes

Changed reveal/identify from teeth to emeralds, lowered the cast time a bit. Future pulls may add more reason to use these spells and in any case this makes them more accessible.

Seance returns an incorrect location a lot of the time and is easily countered, hence the need to cast it multiple times for it to have any use. Vigor cost lowered, mana cost slightly increased.