* Move all epi-related code from egui_glow into eframe
* Move epi stuff from egui-winit into eframe
* Remove mention of epi in egui
* Remove mention of epi in egui_glium
* Remove trait epi::NativeTexture
* Remove confusing mentions of epi
* Refactor egui_web: break up into smaller files
* Clean up feature flags further, and update changelogs
* Clean up check.sh
* Small cleanup of egui_web/Cargo.toml
* Fix dependencies for pure_glow example
* Fix clippy false positive
* Add Shape::Callback to do custom rendering inside of an egui UI
* Use Rc<glow::Context> everywhere
* Remove trait WebPainter
* Add glow::Context to epi::App::setup
* Move texture allocation into epaint/egui proper
* Add TextureHandle
* egui_glow: cast using bytemuck instead of unsafe code
* Optimize glium painter
* Optimize WebGL
* Add example of loading an image from file
* 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
