v0.3.5: fixed sheep bugs involving applying buffs to them

src/com/shatteredpixel/shatteredpixeldungeon/actors/mobs/npcs/Sheep.java

@@ -20,6 +20,7 @@
  */
 package com.shatteredpixel.shatteredpixeldungeon.actors.mobs.npcs;
 
+import com.shatteredpixel.shatteredpixeldungeon.actors.buffs.Buff;
 import com.shatteredpixel.shatteredpixeldungeon.messages.Messages;
 import com.shatteredpixel.shatteredpixeldungeon.sprites.SheepSprite;
 import com.watabou.utils.Random;
@@ -55,6 +56,10 @@ public class Sheep extends NPC {
 	public void damage( int dmg, Object src ) {
 	}
 
+	@Override
+	public void add( Buff buff ) {
+	}
+
 	@Override
 	public void interact() {
 		yell( Messages.get(this, Random.element( LINE_KEYS )) );