* 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
The purpose of this is to expose `frame.storage()` and `frame.storage_mut()` so users can save/load app state from the `App::update` function, without having to add another parameter to that function.
Changes:
* Added `Frame::storage()` and `Frame::storage_mut()`
* `App::update` now takes a `&mut Frame` rather than just `&Frame`
* `Frame` is no longer `Clone` or `Sync` (doesn't have to be since https://github.com/emilk/egui/pull/1366)
* Refactor text layout: don't need &Fonts in all functions
* Replace indexing in Fonts with member function
* Wrap Fonts in a Mutex
* Remove mutex for Font::glyph_info_cache
* Remove RwLock around Font::characters
* Put FontsImpl and GalleyCache behind the same Mutex
* Round font sizes to whole pixels before deduplicating them
* Make TextStyle !Copy
* Implement user-named TextStyle:s
* round font size earlier
* Cache fonts based on family and size
* Move TextStyle into egui and Style
* Remove body_text_style
* Query graphics about max texture size and use that as font atlas size
* Recreate texture atlas when it is getting full
* Move all interior mutability from Context to CtxRef and make it a handle
* Rename `CtxRef` to `Context`
* The old `Context` is now `ContextImpl` and is non-pub
* Add benchmark Painter::rect
Co-authored-by: Daniel Keller <dklr433@gmail.com>
