Bugfix: External spool

Improvement: Use fragments in templates
Features: Manual fill of empty tray
Bump version to 0.1.3

templates/issue.html

@@ -0,0 +1,6 @@
+{% extends 'base.html' %}
+
+{% block content %}
+<h1>Solve issue</h1>
+<h2>TBD</h2>
+{% endblock %}