Yadisk

* Fixed `issue 26`_: ':' 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.

* Fixed a minor bug which could cause a `ReferenceError`
(which would not cause a crash, but still show an error message). The bug
involved using `__del__()` method in `SelfDestructingSession`
to automatically close the sessions it seems to affect primarily old Python
versions (such as 3.4).

* Fixed a bug in `check_token()`: could throw `ForbiddenError` if
the application lacks necessary permissions (`issue 23`_).

* 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.

* Fixed a `TypeError` in `get_public_*` functions when passing `path` parameter
(see `issue 7`_)
* Added `unlimited_autoupload_enabled` attribute for `DiskInfoObject`

* Added `md5` parameter for `remove()`
* Added `UserPublicInfoObject`
* Added `country` attribute for `UserObject`
* Added `photoslice_time` attribute for `ResourceObject`, `PublicResourceObject`
and `TrashResourceObject`