Add rudimentary support for gui windows that you can move around

example_glium/src/main.rs

@@ -8,7 +8,7 @@ use {
         label,
         math::vec2,
         widgets::{Button, Label},
-        Align, Emigui,
+        Align, Emigui, Window,
     },
     emigui_glium::Painter,
     glium::glutin,
@@ -90,6 +90,12 @@ fn main() {
         }
         example_app.ui(&mut region);
         emigui.ui(&mut region);
+
+        // TODO: Make it simpler to show a window
+        Window::new("Test window").show(region.data().clone(), |region| {
+            region.add(label!("Grab the window and move it around!"));
+        });
+
         let mesh = emigui.paint();
         painter.paint(&display, mesh, emigui.texture());
     }