Yadisk-async

&8212; Fixed ivknv/yadisk26: ':' character in filenames causes `BadRequestError`. This is due the behavior of Yandex.Disk's REST API itself but is avoided on the library level with this fix.

&8212; Fixed a bug in `is_file()` and `is_dir()`: a typo was causing `AttributeError` (PR 6).

&8212; Fixed a bug in `check_token()`: could throw `ForbiddenError` if the application lacks necessary permissions ([issue 23](https://github.com/ivknv/yadisk/issues/23)).

&8212; Fixed an issue where `http://` links were not recognized as operation links (they were assumed to always be `https://`, since all the other requests are always HTTPS). Occasionally, Yandex.Disk can for some reason return an `http://` link to an asynchronous operation instead of `https://`. Both links are now recognized correctly and an `https://` version will always be used by `get_operation_status()`, regardless of which one Yandex.Disk returned.

&8212; Fixed `__version__` having the old value

&8212; Fixed `AttributeError` in `SessionWithHeaders` (PR 1)
&8212; Fixed trash bin tests