Evercas

- Rename private method `HashFS.copy` to `HashFS._copy`.
- Add `is_duplicate` attribute to `HashAddress`.
- Make `HashFS.put()` return `HashAddress` with `is_duplicate=True`
when file with same hash already exists on disk.

- Add `HashFS.size()` method that returns the size of all files in
bytes.
- Add `HashFS.count()`/`HashFS.__len__()` methods that return the
count of all files.
- Add `HashFS.__iter__()` method to support iteration. Proxies to
`HashFS.files()`.
- Add `HashFS.__contains__()` method to support `in` operator. Proxies
to `HashFS.exists()`.
- Don\'t create the root directory (if it doesn\'t exist) until at
least one file has been added.
- Fix `HashFS.repair()` not using `extensions` argument properly.

- Rename `HashFS.length` parameter/property to `width`. (**breaking
change**)

- Rename `HashFS.get` to `HashFS.open`. (**breaking change**)
- Add `HashFS.get()` method that returns a `HashAddress` or `None`
given a file ID or path.

- Add `HashFS.get()` method that retrieves a reader object given a
file ID or path.
- Add `HashFS.delete()` method that deletes a file ID or path.
- Add `HashFS.folders()` method that returns the folder paths that
directly contain files (i.e. subpaths that only contain folders are
ignored).
- Add `HashFS.detokenize()` method that returns the file ID contained
in a file path.
- Add `HashFS.repair()` method that reindexes any files under root
directory whose file path doesn\'t not match its tokenized file ID.
- Rename `Address` classs to `HashAddress`. (**breaking change**)
- Rename `HashAddress.digest` to `HashAddress.id`. (**breaking
change**)
- Rename `HashAddress.path` to `HashAddress.abspath`. (**breaking
change**)
- Add `HashAddress.relpath` which represents path relative to
`HashFS.root`.

- First release.
- Add `HashFS` class.
- Add `HashFS.put()` method that saves a file path or file-like object
by content hash.
- Add `HashFS.files()` method that returns all files under root
directory.
- Add `HashFS.exists()` which checks either a file hash or file path
for existence.