egui/examples/retained_image/README.md

```sh
cargo run -p retained_image
```
Move examples out of `eframe/examples` into `examples/` (#1486) * 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 2022-04-13 14:13:24 +00:00			```sh
			`cargo run -p retained_image`
			```