Reactpy

Upgrade `anyio`

- Rename `Renderer` to `Dispatcher` - I think this will reduce confusion since the word "render" is used all over to mean different things.
- `AbstractElement` does not need an `id` attribute - we can just use `id()` instead.
- misc doc updates

Element render functions are no longer coroutines. To new users async functions don't really seem approachable, plus delayed actions are best left to the `use_effect` hook. To compensate we enable the `use_effect` hook to support async functions - docs are added to this effect.

Quick release to publish docs without a mangled dev version visible.

The One With Hooks

This is a huge release that reworks much of IDOM to use a [React-like Hooks](https://reactjs.org/docs/hooks-intro.html) API.

The documentation has been updated to reflect these changes so it's probably best to check the README to learn about the state of the project. In short though...

- Most of React's hooks have been faithfully re-implemented in Python (a new "Life Cycle Hooks" section reflects these additions).
- The only "basic hook" missing from this release is `useContext` given that its most useful in sprawling code-bases. Given that IDOM has no such usage a `use_context` hook isn't useful yet.
- Much of IDOM's internal logic for computing and transmitting layout updates was reworked.
- Updates are no longer computed in parallel and distributed as completed, instead they an executed serially (this may be reverted in a future version). While has negative performance implications in some cases it simplified logic.
- Updates are now transited over the wire using the [JSON-patch](http://jsonpatch.com/) format since the old format assumed on targeted updates would be triggered by imperative code.

Side Notes

- it's now much easier to set up an layout server in a Jupyter notebook - just use `idom.widgets.jupyter.init_display(...)`

IDOM now officially supports referencing arbitrary ES modules as part of its layouts. See [the docs](https://idom.readthedocs.io/en/latest/javascript-modules.html) for more info.

This release also includes a few other quality of life improvements:

- the `vdom()` constructor now supports passing children as positional arguments outside of a list. This comes with the caveat that element attributes must not contain a `tagName` key (which seems like a reasonable concession).
- update calls can now be made from within separate threads. This means when you define an element with `run_in_executor=True` you'll be able to update it later. Until now updates had to be managed from the thread where the layout's event loop was.