tidy up GUI section

[blackholeearth]

tidy up gui section.

some of them are just theme library ( depends on an actual GUI-framework.)

some are just list of gui controls

i split them in new section:

• gui
• theme libs
• collection of controls/widgets

---

new look::

## GUI

### GUI - Framework

* [Avalonia](https://github.com/AvaloniaUI/Avalonia) - A multi-platform .NET UI framework (formerly known as Perspex).
* [Windows UI Library](https://github.com/microsoft/microsoft-ui-xaml) - The Windows UI Library (WinUI) provides official native Microsoft UI controls and features for Windows UWP apps.
* [UNO Platform](https://github.com/unoplatform) - The only platform for building native mobile, desktop and WebAssembly with C#, XAML from a single codebase. Open source and professionally supported. Website: [platform.uno](https://platform.uno/)
* [Xamarin.Forms](https://github.com/xamarin/Xamarin.Forms) - Build native UIs for iOS, Android and Windows from a single, shared C# codebase.
* [Eto.Forms](https://github.com/picoe/Eto) - Cross-platform GUI framework for desktop and mobile applications in .NET and Mono
* [Gtk#](https://github.com/mono/gtk-sharp) - Gtk# is a Mono/.NET binding to the cross platform Gtk+ GUI toolkit and the foundation of most GUI apps built with Mono
* [QtSharp](https://github.com/ddobrev/QtSharp) - Mono/.NET Bindings for Qt
* [SciterSharp](https://github.com/ramon-mendes/SciterSharp) - Create .NET cross-platform desktop apps using not just HTML, but all features of Sciter engine: CSS3, SVG, scripting, AJAX, <video>... Sciter is free for commercial use
* [XWT](https://github.com/mono/xwt) - A cross-platform UI toolkit for creating desktop applications with .NET and Mono
* [Qml.Net](https://github.com/qmlnet/qmlnet) - A cross-platform Qml/.NET integration for Mono/.NET/.NET Core
* [Lara](https://github.com/integrativesoft/lara) - Lara Web Engine is a library for developing Web user interfaces in C#
* * [Neutronium](https://github.com/NeutroniumCore/Neutronium) - Build .NET desktop applications using HTML, CSS, javascript and MVVM bindings such as with WPF.

### GUI - Themed  Control kits

* [Modern UI for WPF - MUI](https://github.com/firstfloorsoftware/mui) - Set of controls and styles to convert WPF applications into a great looking Modern UI apps.
* [MahApps.Metro](https://github.com/MahApps/MahApps.Metro) - Toolkit for creating Metro-styled WPF apps
* [MaterialSkin](https://github.com/IgnaceMaes/MaterialSkin) - Theming .NET WinForms, C# or VB.Net, to Google's Material Design principles.
* [AdonisUI](https://github.com/benruehl/adonis-ui) - Lightweight UI toolkit for WPF applications offering classic but enhanced Windows visuals.
* [Bunifu UI Framework](https://bunifuframework.com) - Carefully crafted Winforms controls and components for creating stunning modern application UI. **[$]**
* [HandyControl](https://github.com/HandyOrg/HandyControl) - Contains some simple and commonly used WPF controls
* [MaterialDesignInXamlToolkit](http://materialdesigninxaml.net/) - Toolkit for creating Material Design styled WPF apps
* [UWP Community Toolkit](https://github.com/windows-toolkit/WindowsCommunityToolkit) - The UWP Community Toolkit is a collection of helper functions, custom controls, and app services. It simplifies and demonstrates common developer tasks building UWP apps for Windows 10.
* [Empty Keys UI](https://www.emptykeys.com/ui_library/) - Multi-platform and multi-engine XAML based user interface library **[Free][Proprietary]**

### GUI - other

* [Callisto](https://github.com/timheuer/callisto) - A control toolkit for Windows 8 XAML applications. Contains some UI controls to make it easier to create Windows UI style apps for the Windows Store in accordance with Windows UI guidelines.
* [WinApi](https://github.com/prasannavl/WinApi) - A simple, direct, ultra-thin CLR library for high-performance Win32 Native Interop with automation, windowing, DirectX, OpenGL and Skia helpers.
* [ObjectListView](http://objectlistview.sourceforge.net/cs/index.html) - ObjectListView is a C# wrapper around a .NET ListView. It makes the ListView much easier to use and teaches it some new tricks
* [DockPanelSuite](https://sourceforge.net/projects/dockpanelsuite/) - The Visual Studio inspired docking library for .NET WinForms
* [AvalonEdit](https://github.com/icsharpcode/AvalonEdit) - The WPF-based text editor component used in SharpDevelop