add README

README.md

@@ -0,0 +1,9 @@
+layers_content_toolbox
+======================
+
+Package for (KLayout)[https://www.klayout.de] adding two items to the right-click menu in the "Layers" pane:
+
+- `Make All Valid`: Makes all layers valid (interactable) and visible. Adds hotkey Ctrl+Shift+V.
+- `Change Layer for Objects`: Same as `Edit -> Selection -> Change Layer`
+
+![Context menu as of v0.30.0](./doc/context_menu.jpg)

grain.xml

@@ -7,7 +7,7 @@
  <api-version/>
  <title>Layers context toolbox</title>
  <doc>Adds items to the "Layers" pane context menu: "Change Layer of Objects", "Make All Valid"</doc>
- <doc-url/>
+ <doc-url>README.md</doc-url>
  <url/>
  <license>GPLv3</license>
  <author>Jan Petykiewicz</author>