Added .contains() check for dumpGameAssetJSON() so duplicate items and blocks will not get added to the list.
Added .contains() check for dumpGameAssetJSON() so duplicate items and blocks will not get added to the list.

Maxwolf/MC-MineAPI.Java,Maxwolf/MineAPI.Java,FoxBytes/MineAPI.Java,Maxwolf/MineAPI.Java,Maxwolf/MC-MineAPI.Java,FoxBytes/MineAPI.Java