show engine errors in infobox && add new error alert

searx/templates/oscar/results.html

@@ -94,6 +94,16 @@
             {% if number_of_results != '0' %}
                 <p><small>{{ _('Number of results') }}: {{ number_of_results }}</small></p>
             {% endif %}
+
+            {% if unresponsive_engines and results|length >= 1 %}
+            <div class="alert alert-danger fade in" role="alert">
+                <p>{{ _('Engines cannot retrieve results') }}:</p>
+                {% for engine_name, error_type in unresponsive_engines %}
+                {{ engine_name }} ({{ error_type }}){% if not loop.last %}, {% endif %}
+                {% endfor %}
+            </div>
+            {% endif %}
+
             {% if infoboxes %}
                 {% for infobox in infoboxes %}
                     {% include 'oscar/infobox.html' %}