* 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>
* Rename epaint feature "persistence" to "serialize"
* Add separate "serialize" feature to egui
* egui_demo_lib: separate serialize and persistence features
* Add App::persist_native_window and App::persist_egui_memory
Controls what gets persisted
Label text will now be centered, right-aligned and/or
justified based on the layout.
Galleys are no longer always pivoted in the left top corner,
so now have a Rect rather than just a size.
* First pass (missing rendering the bar)
* Render horizontal bars, and change Window scroll API
* emath: add impl Index + IndexMut for Align2
* Scrolling: fix subtle sizing bugs
* Add horizontal scrolling to color test
* try to wrap content before showing scrollbars, + add auto-shrink option
* Add hscroll to the misc demo window
* Fix for putting wrapping labels in an infinitely wide layout
* Add a egui_asserts to protect against nans in the layout engine
* Add line about horizontal scrolling to changelog
* Add example to docs of ScrollArea
* code cleanup
* Allow using the layout cursor to restrict available area
* Avoid id clashes when putting panels inside a Ui
* Panels: Propagate height/width range to inner Ui
* Allow easy placement of panels inside of Ui:s
* demo: simplify Windows with Panels demo
