Add clipboard.min.js to layout

This is needed for the copy button on file asset uploading. Rather than
including it on all pages that could feature the file uploader it's now
loaded globally.

src/templates/layout.pug

@@ -32,8 +32,7 @@ html(lang="en")
 		script(src="{{ url_for('static_pillar', filename='assets/js/vendor/jquery-3.1.0.min.js')}}")
 		script(src="{{ url_for('static_pillar', filename='assets/js/vendor/jquery.typeahead-0.11.1.min.js')}}")
 		script(src="{{ url_for('static_pillar', filename='assets/js/vendor/js.cookie-2.0.3.min.js')}}")
-
-		script.
+		script(src="{{ url_for('static_pillar', filename='assets/js/vendor/clipboard.min.js')}}")
 
 		| {% if current_user.has_cap('subscriber') %}
 		| {# Only load if we can comment (for converting markdown as-we-type) #}