v0.3.1a: cleaned up quickslot autotargeting:

- quickslots will now only autotarget enemies they can actually auto-aim for.
- cleaned up code for determining which items should use targeting

src/com/shatteredpixel/shatteredpixeldungeon/items/artifacts/EtherealChains.java

@@ -55,6 +55,7 @@ public class EtherealChains extends Artifact {
 		charge = 5;
 
 		defaultAction = AC_CAST;
+		usesTargeting = true;
 	}
 
 	@Override