Stygian Abyss dungeon Stealables

Added new Stygian Abyss dungeon stealable artifacts Crown of Arcane Temperament, Light in the Void, Valkyrie's Glaive, and Staff of Resonance. Also updated the entries in StealableArtifactSpawner to include the new stealables so they will spawn with the [genstealarties command. May have to [remotestealarties and re-generate them after this fix. Items are OSI accurate except for hues, which are as close as I could get them. Links to confirm: http://www.uoguide.com/Stygian_Abyss_stealables http://uo2.stratics.com/items/stygian-abyss-stealables