- Add `mix` method to mix two color.
- Export `ui::theme::*` to crate root, before `use
ui:theme::ActiveTheme` to `use ui::ActiveTheme`.
## Break Changes
- Moved `ui::theme::Colorize` to `ui::Colorize`.
- Merged `ColorExt` to `Colorize`.
- Renamed `to_hex_string` to `to_hex`, `parse_hex_string` to
`parse_hex`.
## Break Changes
- Renamed `DockItemState` to `PanelState`.
- Renamed `DockItemInfo` to `PanelInfo`.
- Update `cx` type from `WindowContext` to `AppContext` for Panel trait
`panel_name` method.
## TODO
- [ ] Support merge panels into TabPanel.
- [ ] Support split panels into Tile.
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Co-authored-by: Jason Lee <huacnlee@gmail.com>
