Add _WIN64 check to LZF source
Merge pull request #422 from andrewcollette/issue_419

Add _WIN64 check to LZF source
Fix issue #420 (again).

This updated check allows for arbitrary chunks for dimensions where maxshape is None.
Else, the chunk size must still be lower than the shape.
Merge pull request #423 from pdebuyl/alternative_chunks_check

Fix issue #420 (again).