ensure base templates returns 0 length file as they should

templates/null.tpl

@@ -10,46 +10,46 b' Subtemplates can Override Blocks to define their custom reresentation.'
 If one of the block you do overrite is nt a leave block, consider
 calling super.
 
-{% block nonLeaveBlock %}
+{%- block nonLeaveBlock -%}
     #add stuff at beginning
     {{ super() }}
     #add stuff at end
-{% endblock nonLeaveBlock %}
+{%- endblock nonLeaveBlock -%}
 
 consider calling super even if block is leave block, we might insert more block later.
 
 #}
 
-{% block codecell scoped  %}
-{% block in_prompt %}{% endblock in_prompt %}
-{% block input %}{% endblock input %}
-{% if cell.outputs %}
-{% block output_prompt %}{% endblock output_prompt %}
+{%- block codecell scoped  -%}
+{%- block in_prompt -%}{%- endblock in_prompt -%}
+{%- block input -%}{%- endblock input -%}
+{%- if cell.outputs -%}
+{%- block output_prompt -%}{%- endblock output_prompt -%}
 {%- for output in cell.outputs -%}
     {%- if output.output_type in ['pyout']%}
-        {% block pyout scoped %}{% endblock pyout %}
-    {%- elif output.output_type in ['stream'] %}
-       {% block stream scoped %}{% endblock stream %}
-    {%- elif output.output_type in ['display_data'] %}
-        {% block display_data scoped %}{% endblock display_data %}
-    {%- elif output.output_type in ['pyerr'] %}
-        {% block pyerr scoped %}
-        {%- for line in output.traceback %}
-            {% block traceback_line scoped %}{% endblock traceback_line %}
-        {%- endfor %}
-        {% endblock pyerr %}
-    {%- endif %}
+        {%- block pyout scoped -%}{%- endblock pyout -%}
+    {%- elif output.output_type in ['stream'] -%}
+       {%- block stream scoped -%}{%- endblock stream -%}
+    {%- elif output.output_type in ['display_data'] -%}
+        {%- block display_data scoped -%}{%- endblock display_data -%}
+    {%- elif output.output_type in ['pyerr'] -%}
+        {%- block pyerr scoped -%}
+        {%- for line in output.traceback -%}
+            {%- block traceback_line scoped -%}{%- endblock traceback_line -%}
+        {%- endfor -%}
+        {%- endblock pyerr -%}
+    {%- endif -%}
 {%- endfor -%}
-{% endif -%}
-{%- endblock codecell %}
+{%- endif -%}
+{%- endblock codecell -%}
 
-{% block markdowncell scoped %}{% endblock markdowncell %}
+{%- block markdowncell scoped -%}{%- endblock markdowncell -%}
 
-{% block headingcell scoped %}
-{% endblock headingcell %}
+{%- block headingcell scoped -%}
+{%- endblock headingcell -%}
 
-{% block rawcell scoped %}
-{% endblock rawcell %}
+{%- block rawcell scoped -%}
+{%- endblock rawcell -%}
 
-{% block unknowncell scoped %}
-{% endblock unknowncell %}
+{%- block unknowncell scoped -%}
+{%- endblock unknowncell -%}