Implement stat returning file size and a/m/c-time.

Fix FS B-tree lookups by using unsigned_compare where appropriate.

Do simple (ASCII-only) case folding when calculating file name hashes.

Remove .merlin files.

Remove some debug prints.

Parse sparse bytes extended field.

Turns out, floor was the right choice. Just don't return empty stream if there is no floor value.

Implement XField parsing, this should enable to access the DStream size.

Begin work on stat operation.

Add InvalidMax dummy FsObject, correctly implement ordering for Invalid* FsObjects.

Implement directory entry lookup.

Fix indentation in nested match.

Fix B-tree traversal by using ceil instead of floor in stream_from function

Refactor FileSystem module, hide internals.

Implement upper bound for B-Tree slicing.

Small refactoring for lower-bound handling.

Begin sub-Btree extraction, implement lower-bound, TODO: upper-bound.

Remove obsolete NotImplemented errors.

Implement BtreeTraversal.fold_s and re-implement iter on top of fold_s.

Store superblock in FS structure.