* Move examples out of eframe/examples into examples/
Give each example a `Cargo.toml` and `src/main.rs`.
This makes it easier for people to use as templates.
* Update README.md with more deps needed on vanilla Ubuntu
* Install libgtk-3-dev on CI, hoping that will fix something
* Switch to using glow as the default renderer both on native and the web
* Simplify code to find WebGL context for glow
* egui_web: make webgl an opt-in feature
* Stop using deprecated WEBGL_debug_renderer_info
* 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
