Fix double error checking in ChunkConverter

Now all exceptions are converted to IOExceptions with location added.
Fix ClassCastExceptions when encountering invalid NBT
Convert player inventories
Fix error in 8d15524ab519d922bad50e91071309605f9b7de5: check the type of list elements

Checking the type of the list will always return TAG_List, checking the
type of the elements in the list will return the intended tag type.
Convert items in tile entities too
Formatting