Dash

Changed
- [547](https://github.com/plotly/dash/pull/547)
- `assets_folder` argument now defaults to 'assets'
- The assets folder is now always relative to the given root path of `name` argument, the default of `__main__` will get the `cwd`.
- No longer coerce the name argument from the server if the server argument is provided.

Fixed
- [547](https://github.com/plotly/dash/pull/547)
- Asset blueprint takes routes prefix into it's static path.
- Asset url path no longer strip routes from requests.
- [548](https://github.com/plotly/dash/pull/548) Remove print statement from PreventUpdate error handler.
- [524](https://github.com/plotly/dash/pull/524) Removed ComponentRegistry dist cache.

Fixed
- [522](https://github.com/plotly/dash/pull/522) Fix typo in some exception names
- [renderer110](https://github.com/plotly/dash-renderer/pull/110)
- Keep the config store state on soft reload.
- AppProvider returns `Loading...` if no configs as before [renderer108](https://github.com/plotly/dash-renderer/pull/108).

Fixed
- [518](https://github.com/plotly/dash/pull/518) Always skip `dynamic` resources from index resources collection.

Added
- [483](https://github.com/plotly/dash/pull/483) Experimental `--r-prefix` option to `dash-generate-components`, optionally generates R version of components and corresponding R package.

Added
- [490](https://github.com/plotly/dash/pull/490) Add `--ignore` option to `dash-generate-components`, defaults to `^_`.

Removed
- [renderer108](https://github.com/plotly/dash-renderer/pull/108) Unused login api and Authentication component

Fixed
- Add `key` to rendered components, fixing [renderer379](https://github.com/plotly/dash-core-components/issues/379)

Added
- [487](https://github.com/plotly/dash/pull/487) Add specific Dash exception types to replace generic exceptions (`InvalidIndexException`, `DependencyException`, `ResourceException`)