* Add syntax highlighing feature to egui_extras
Enable "syntect" feature for great syntax highlighting of any language.
If not a simple fallback is used that works fine for C++, Rust, Python
* Check --no-default-features of egui_extras on CI
* spelling
* Fix building egui_extras without additional features
Context::current_rendering_viewport was replaced by Context::get_viewport_id
Added Context::get_parent_viewport_id
Changed Context::run to need parent_viewport_id
Changed Context::beagin to need parent_viewport_id
Added ImplContext::frame_stack
Some work on making posibile to render multiples frames at the same time
A lot of more things in glutin backend is not Arc<RwLock<T>>
* Add Separator::grow and Separator::shrink
* Be more conservative with the clipping in ScrollArea:s
* Add test of the growing separator
* Improve test output
* Update changelog
* Add back a little bit more clipping
* Make the minimum scroll handle length a bit longer
* More clip rect tweaks
