Add isNPCPlayer api

[tanyaofei]

Hi~

I wrote a plugin that is listening to the EntityEquipmentPacket to rewrite some equipments, but I can't detect the player is a npc player(lay and spin), so when a player commanded spin or lay, my plugin will not work cause their uuid are not the same. Hope that I can detect the player is a npc player so that i can rewrite the equipments.

Maybe you can add an api public boolean isNPCPlayer(Player player) ?

[gecolay]

@tanyaofei take a look at this. There is no need for GSit to provide this method