Fix compile issues with the latest spigot version (#1510)

Author: derklaro

src/main/java/com/comphenix/protocol/events/SerializedOfflinePlayer.java

@@ -45,6 +45,7 @@
 import org.bukkit.*;
 import org.bukkit.entity.EntityType;
 import org.bukkit.entity.Player;
+import org.bukkit.profile.PlayerProfile;
 
 import com.comphenix.protocol.utility.ByteBuddyFactory;
 
@@ -176,7 +177,12 @@ public long getLastPlayed() {
 	public UUID getUniqueId() {
 		return uuid;
 	}
-	
+
+	@Override
+	public PlayerProfile getPlayerProfile() {
+		return null;
+	}
+
 	@Override
 	public String getName() {
 		return name;