Widgets / Allow duplicate even if not editable.
Widgets / Thumbnail view / Provide list of layers in a menu (#279).

In templates use
```
<div class="md-links md-links-{id}">
```
to create a div with all links (grouped by protocol).

or
```
<div class="md-links md-links-{id}" data-filter="application/vnd.ogc.wms_xml">
```
to only create a div with link of WMS (eg. in thumbnail view mode).