Added trade option for Enchanter's Amulet, added +1 int to Scarab Armlet, made...

Added trade option for Enchanter's Amulet to Trader in store, added +1 int to Scarab Armlet(to gain usage again), made Magic Ring a shield item with a min dex of 20 required(allows for normal gem ring use also) and made amulet 1 in 3 chances(from 1 in 4) again at the swamp chest. This actually gives mages a boost, even if they need to spend stats for 20 dex to use the Magic Ring, since 20 dex costs less than 2 int points(in character points) at higher int(~100) and since they can make use of outfits anyway. Choices, choices!