v0.7.4: corrected new logic causing piranhas to get surprise attacked

core/src/main/java/com/shatteredpixel/shatteredpixeldungeon/actors/mobs/Piranha.java

@@ -87,6 +87,15 @@ public class Piranha extends Mob {
 		return Random.NormalIntRange(0, Dungeon.depth);
 	}
 	
+	@Override
+	public int defenseSkill( Char enemy ) {
+		enemySeen = state != SLEEPING
+				&& this.enemy != null
+				&& fieldOfView[this.enemy.pos]
+				&& this.enemy.invisible == 0;
+		return super.defenseSkill( enemy );
+	}
+	
 	@Override
 	public void die( Object cause ) {
 		super.die( cause );