V0.1.0: rebalanced Scroll of Psionic Blast

-Scroll is now more powerful and dangerous, more rare
-Only bosses can resist psionic blast now, Yog is immune

src/com/shatteredpixel/shatteredpixeldungeon/actors/mobs/Elemental.java

@@ -100,7 +100,6 @@ public class Elemental extends Mob {
 		IMMUNITIES.add( Burning.class );
 		IMMUNITIES.add( Fire.class );
 		IMMUNITIES.add( WandOfFirebolt.class );
-		IMMUNITIES.add( ScrollOfPsionicBlast.class );
 	}
 	
 	@Override