Add vendor:microui

This is a direct port in Odin, not bindings; utilizing Odin's rich type system

vendor/README.md

@@ -6,6 +6,12 @@ Its use is similar to that of `core:` packages, which would be available in any
 
 Presently, the `vendor:` collection comprises the following packages:
 
+## microui
+
+A tiny, portable, immediate-mode UI library written in Odin. (Ported from [rxi/microui](https://github.com/rxi/microui).)
+
+This package is available under the MIT license. See `LICENSE` for more details.
+
 ## OpenGL
 
 Bindings for the OpenGL graphics API and helpers in idiomatic Odin to, for example, reload shaders when they're changed on disk.

vendor/microui/LICENSE

@@ -0,0 +1,21 @@
+Original work: Copyright (c) 2020 rxi
+Modified work: Copyright (c) 2020 oskarnp
+Modified work: Copyright (c) 2021 gingerBill
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

vendor/microui/README.md

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+# microui-odin
+
+## Description
+A tiny, portable, immediate-mode UI library written in Odin. (Ported from [rxi/microui](https://github.com/rxi/microui).)
+
+![screenshot](https://user-images.githubusercontent.com/3920290/56437823-c3dcdb80-62d8-11e9-978a-a0739f9e16f0.png)
+
+[**Browser Demo**](https://floooh.github.io/sokol-html5/sgl-microui-sapp.html) (rxi's microui)
+
+## Features
+* Tiny: around `1200 sloc` of Odin
+* Works within a fixed-sized memory region: no additional memory is
+  allocated
+* Built-in controls: window, panel, button, slider, textbox, label,
+  checkbox, wordwrapped text
+* Easy to add custom controls
+* Simple layout system
+
+## Notes
+* This library assumes you are using the latest nightly build or GitHub master of the Odin compiler. Since Odin is still under development this means this library might break in the future. Please create an issue or PR if that happens. Last verified against: odin version dev-2021-07:481fc8a5
+* The library expects the user to provide input and handle the resultant
+  drawing commands, it does not do any drawing itself.
+
+## License
+This library is free software; you can redistribute it and/or modify it
+under the terms of the MIT license. See [LICENSE](LICENSE) for details.