Check for compression type.
No longer try to analyse the chunk_header if it is out-of-file.
Decompress chunks and verify do a very basic check.
Check the first 3 and last 1 byte of the NBT binary (not a full parsing).
Better tests in region analysis.
Change order of tests, so primary problem is shown first.
Add tests for timestamps
52 unittests for region.py
Just about all fail yet ...