refactor project structure (start of redoing atomic branch without atomics)

src/widget/position/layer.rs

@@ -0,0 +1,23 @@
+use crate::prelude::*;
+
+pub struct LayerOffset {
+    pub inner: WidgetId,
+    pub offset: usize,
+}
+
+impl Widget for LayerOffset {
+    fn draw(&mut self, painter: &mut Painter) {
+        for _ in 0..self.offset {
+            painter.next_layer();
+        }
+        painter.widget(&self.inner);
+    }
+
+    fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len {
+        ctx.width(&self.inner)
+    }
+
+    fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len {
+        ctx.height(&self.inner)
+    }
+}