Pyryver

This post-release fixes a minor typo in `Object.get_app_link()` (10), in addition to some minor documentation formatting issues.

For an example on how to use the new connection features, see [Realtime Quickstart](https://pyryver.readthedocs.io/en/latest/intro.html#realtime-quickstart) or the [Example Usage](https://pyryver.readthedocs.io/en/latest/index.html#example-usage) on the homepage on Read the Docs.

Minor bugfix release.

Changes:
* Fix bug in connection loss error handling for `RyverWS`. In previous releases, sometimes during the connection loss error handlers, an `asyncio.InvalidStateError` may be thrown, caused by calling `Future.set_exception()` on a future that's already done. This release fixes this bug.

First beta release of v0.4.0.

Small bugfixes and improvements. Changelog:
- `__repr__` has been improved for a lot of classes derived from `Object`. Objects with names will have their names shown in their `__repr__`, and some other classes such as `Message`s will have even more information. (ab3f9f9)
- `GroupChatMember`'s `as_user()` method has been made async because it needs to fetch additional information. (11ca311)
- Fixed `File.download_data()`, which was broken by 0b5bc03. (0e33571)
- Add methods `GroupChat.join()` and `GroupChat.leave()` for joining and leaving forums and teams. (d14ccca)

This release is on PyPI.