Fixed Crash in 1.4.7

Fixes crash

java.lang.NoSuchMethodError: net.minecraft.server.v1_4_R1.EntityHuman.getBukkitEntity()Lorg/bukkit/entity/HumanEntity;
	at com.topcat.npclib.DragonAntiPvPListener.nms.NPCEntity.a(NPCEntity.java:47)
	at net.minecraft.server.v1_4_R1.EntityHuman.p(EntityHuman.java:728)
	at net.minecraft.server.v1_4_R1.PlayerConnection.a(PlayerConnection.java:1103)
	at net.minecraft.server.v1_4_R1.Packet7UseEntity.handle(SourceFile:36)
	at net.minecraft.server.v1_4_R1.NetworkManager.b(NetworkManager.java:290)
	at net.minecraft.server.v1_4_R1.PlayerConnection.d(PlayerConnection.java:113)
	at net.minecraft.server.v1_4_R1.ServerConnection.b(SourceFile:39)
	at net.minecraft.server.v1_4_R1.DedicatedServerConnection.b(SourceFile:30)
	at net.minecraft.server.v1_4_R1.MinecraftServer.r(MinecraftServer.java:598)
	at net.minecraft.server.v1_4_R1.DedicatedServer.r(DedicatedServer.java:224)
	at net.minecraft.server.v1_4_R1.MinecraftServer.q(MinecraftServer.java:494)
	at net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java:427)
	at net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:849)