Changelog:

0.7.0b0:

Method to convert regions to the sponge schematic NBT format
Fix crash with litematics created by newer versions of Litematica "id -> The required key is missing in the (Tile)Entity's NBT Compound",
It was caused by Litematica no longer specifying a TileEntity's ID in its own NBT structure
(it can be assumed by looking the block at the TileEntity's coordinates)
Made internal list fields access only (Region#entities, Region#tile_entities, Region#block_ticks, Region#fluid_ticks)