A lot of work

* moved all ugui code to lib/ugui.c3l and made it a library/module
* started work on a sdl3 renderer, with shaders etc
* added the new sdl3.c3l library as a dependency
* makefile is for the renderer

resources/shaders/source/rect.frag.glsl

@@ -0,0 +1,9 @@
+#version 450
+
+layout(location = 0) in vec4 col;
+layout(location = 0) out vec4 fragColor;
+
+void main()
+{
+	fragColor = col;
+}