Merge pull request #735 from Felk/patch-1

GUI: remove rise-ui, add OrbTk

README.md

@@ -1092,6 +1092,7 @@ See also [Are we game yet?](http://arewegameyet.com)
 
 * [autopilot-rs/autopilot-rs](https://github.com/autopilot-rs/autopilot-rs) — A simple, cross-platform GUI automation library for Rust.
 * [maps4print/azul](https://github.com/maps4print/azul) — A free, functional, IMGUI-oriented GUI framework for rapid development of desktop applications written in Rust, supported by the Mozilla WebRender rendering engine. [<img src="https://api.travis-ci.org/maps4print/azul.svg?branch=master">](https://travis-ci.org/maps4print/azul)
+* [OrbTk](https://gitlab.redox-os.org/redox-os/orbtk) — The Orbital Widget Toolkit is a multi platform (G)UI toolkit using SDL2 [![Build status](https://gitlab.redox-os.org/redox-os/orbtk/badges/master/build.svg)](https://gitlab.redox-os.org/redox-os/orbtk/pipelines)
 * [PistonDevelopers/conrod](https://github.com/PistonDevelopers/conrod/) — An easy-to-use, immediate-mode, 2D GUI library written entirely in Rust [<img src="https://api.travis-ci.org/PistonDevelopers/conrod.svg?branch=master">](https://travis-ci.org/PistonDevelopers/conrod)
 * [rise-ui](https://github.com/rise-ui/rise) — Simple component-based cross-Platform GUI Toolkit for developing beautiful and user-friendly interfaces.