add option to sync world save data & level states

[Jenna1337]

add option to sync world save data & level states. this would also sync inventory.

[Jenna1337]

I wrote listeners to listen when the save data changes, but I still need to go trough and find out what exactly needs to be synced, and what doesn't need to be synced, and figure out how to represent all that data as something that can be transmitted.