Containers or blocks with NBT should be saved #4
Description
Current Behaviour
Currently, only block states are saved and not their extra NBT data if they have any.
Desired Behaviour
Blocks with NBT data to save should be added to the blocklist as a separate block. Specifically, in the block list, instead of being the index of the blocktype (short), it should be the index of extra data blocks (a new list for blocks with more data).
To differentiate between the lists, the index for the extra block list should be a negative short (shorts are signed in java, so we aren't using half of them if we start at 0 anyway).
The extra data block should be saved as an additional section in the save files.