Airfs

---------------

Fixes:

* Trying to open a file in ``a`` or ``x`` mode now raise ``PermissionError`` if not
enough permission to determinate if the file already exists.
* Fix ``OSError`` exception conversion in ``copy`` and ``copyfile``.
* ``copy`` and ``copyfile`` now tries to copy if no read access but write access,
instead of raising ``PermissionError`` because unable to check the parent directory
first.
* Azure: Fix error when trying to read an existing blog due to bad name handling.
* Azure: Fix query string in blob object path because not removed from URL.
* Azure: Fix error when opening a blob in ``w`` mode if no permission to read it.

Contributors:

* Thanks to Stewart Adam (stewartadam) for the tests and fixes for Azure.

---------------

Add support for following storage:

* Microsoft Azure Blob Storage
* Microsoft Azure File Storage

Improvements:

* ``io.RawIOBase`` can now be used for storage that supports random write access.
* OSS: Copy objects between OSS buckets without copying data on the client when
possible.

Deprecations:

* Warn about Python 3.4 deprecation in next version.

Fixes:

* Fix unsupported operation not risen in all cases with raw and buffered IO.
* Fix call of ``flush()`` in buffered IO.
* Fix file methods not translate storage exception into ``OSError``.
* Fix file not create on open in write mode (Was only created on flush).
* Fix file closed twice when using context manager.
* Fix root URL detection in some cases.
* Fix too many returned result when listing objects with a count limit.
* Fix error when trying to append on a not existing file.
* Fix ``io.RawIOBase`` not generating padding when seeking after the end of the file.
* OSS: Fix error when listing objects in a not existing directory.
* OSS: Fix read error if try to read after the end of the file.
* OSS: Fix buffered write minimum buffer size.
* OSS: Clean up multipart upload parts on failed uploads.
* OSS: Fix error when opening an existing file in 'a' mode.
* S3: Fix error when creating a bucket due to an unspecified region.
* S3: Fix unprocessed error in listing bucket content of a not existing bucket.
* S3: Clean up multipart upload parts on failed uploads.
* S3: Fix missing transfer acceleration endpoints.
* Swift: Fix error when opening an existing file in 'a' mode.

Contributors:

* Thanks to Stewart Adam (stewartadam) for the early tests and fixes for Azure.

---------------

New standard library equivalent functions:

* ``os.listdir``, ``os.lstat``, ``os.remove``, ``os.rmdir``, ``os.scandir``,
``os.stat``, ``os.unlink``, ``os.path.getctime``, ``os.path.islink``,
``shutil.copyfile``.

Improvements:

* Copy of objects from and to the same storage is performed directly on remote server if
possible.
* Now raises ``io.UnsupportedOperation`` if an operation is not compatible with the
current storage, this applies to all newly created function and following existing
functions: ``getsize``, ``getmtime``, ``mkdir``.

Fixes:

* ``io.BufferedIOBase.read`` now returns empty bytes instead of raising exception when
trying to read if seek already at end of the file.
* ``copy`` destination can now be a storage directory and not only a local directory.
* ``copy`` now checks if destination parent directory exists and if files are not the
same file and raise proper exceptions.
* ``mkdir``: missing ``dir_fd`` argument.
* ``isdir`` now correctly handle "virtual" directories (Directory that don't exist as a
proper object, but exists in another object path).

---------------

New standard library equivalent functions:

* ``os.path.exists``, ``os.path.isabs``, ``os.path.isdir``, ``os.path.ismount``,
``os.path.samefile``, ``os.path.splitdrive``, ``os.makedirs``, ``os.mkdir``.

Backward incompatible change:

* ``mount`` argument ``extra_url_prefix`` is renamed to more relevant and clearer
``extra_root``.

Improvements:

* No buffer copy when using ``io.BufferedIOBase.read`` with exactly buffer size. This
may lead to performance improvement.
* Minimum packages versions are set in setup based on packages changelog or date.

Fixes:

* ``isfile`` now correctly returns ``False`` when used on a directory.
* ``relpath`` now keeps ending ``/`` on storage path (Directory marker).

---------------

The first version that implements the core machinery.

Provides storage equivalent functions of:

* ``open`` / ``io.open``, ``shutil.copy``, ``os.path.getmtime``, ``os.path.getsize``,
``os.path.isfile``, ``os.path.relpath``.

Provide storage objects abstract classes with the following interfaces:

* ``io.RawIOBase``, ``io.BufferedIOBase``.

Add support for following storage:

* Alibaba Cloud OSS
* AWS S3
* OpenStack Swift

Add read-only generic HTTP/HTTPS objects support.

Known issues
------------

* Append mode doesn't work with ``ObjectBufferedIOBase``.
* Following functions does not follow symlinks yet:

* For path target and parents directories: ``airfs.rmdir``, ``airfs.samefile``,
``airfs.copy``, ``airfs.copypath``.
* For parent directories: ``airfs.makedirs``, ``airfs.mkdir``, ``airfs.remove``,
``airfs.lstat``, ``airfs.lexists``, ``airfs.islink``