* Rename `CursorPair` to `CursorRange`
* Easymark editor: add keyboard shortcuts to toggle bold, italics etc
* Split up TextEdit into separate files
* Add TextEdit::show that returns a rich TextEditOutput object with response, galley and cursor
* Rename text_edit::State to TextEditState
This refactors the widget state storage introduced by @optozorax in https://github.com/emilk/egui/pull/257
* Unify the four buckets (`data`, `data_temp`, `id_data` and `id_data_temp`) into a single `data`.
* Less complexity, and also less chance of error (storing in one bucket, reading from another).
* Store data by `Id` and `TypeId`.
* Users can thus reuse the same `Id` to store many types.
* Uses a simple xor of id and typeid, which is fast and good since both id and typeid are already high-entropy hashes.
* Use different suffixes on the functions to pick if you want the data persisted or not (`get_temp`, `insert_persisted`, etc).
* Writing with one suffix and reading with the other works.
* To store state not bound to a specific `Id` (i.e. only based on type), use the new `Id::null` as the key.
* Move window building to egui-winit
* Move icon loading to egui-winit
* `use glow::HasContext;` -> `use glow::HasContext as _;`
* Move FileStorage into epi behind a feature flag
* De-duplicate screen_size_in_pixels and native_pixels_per_point
* Move creation of FileStorage to epi
* Handle epi app output (window size changes etc) in egui-winit
* Move app and memory persistence and autosave logic to egui-winit
* fix check.sh
* Make the epi backend opt-in for egui_glium and egui_glow
* Fix persistence
* Add integration name to epi::IntegrationInfo and the demo
* Clean up Cargo.toml files and fix making egui_glium optional
* fix typo
* Make egui_glium compile without the `epi` feature
* Make egui_glow and opt-in backend for eframe
* Add egui_glow to Cargo.toml and to CI
* Reference egui_glow where egui_glium is mentioned
* Remove path-patches from root Cargo.toml
* Add instructions on how to enable the glow backend of eframe