fix

1. fix bugs in spawning tombstone if players died because of falling in the void

2. fix bugs when people died in the same position the new data will overwrite the old one

features

1. if your tomb was spawn near the bottom of the world and you died because of falling out of the world ,the glass spawned below the pot will not be removed after you get your items in order to keep player safe ,this feature may be expended to the world of end to make people get their items much easier

Add Config File

1. add config to control server whether check the distance of players and tombstone so that player do not need to interactive with the flower pot , but turn it off may reduce server cost