Player: remove dataPacket() and directDataPacket()

I considered renaming sendDataPacket() to dataPacket() to reduce the BC breaks, but the parameter set has changed, which might cause astonishing behaviour, so it's better to break it in a loud way. Also, this has a clearer name.

src/pocketmine/entity/Living.php

@@ -341,7 +341,7 @@ abstract class Living extends Entity implements Damageable{
 			$pk->duration = $effect->getDuration();
 			$pk->eventId = MobEffectPacket::EVENT_ADD;
 
-			$player->dataPacket($pk);
+			$player->sendDataPacket($pk);
 		}
 	}