Add templatetafs.py and user the title filter for list titles

Signed-off-by: Nir Izraeli <nirizr@gmail.com>

Author: nirizr

server/collab/templates/list.html

@@ -9,7 +9,7 @@
   <thead>
     <tr>
       {% for header in headers %}
-      <th>{{ header }}</th>
+      <th>{{ header|title }}</th>
       {% endfor %}
       <th></th>
     </tr>

server/templatetags.py

@@ -0,0 +1,10 @@
+from django import template
+
+register = template.Library()
+
+
+@register.filter
+def lookup(d, key):
+  if key not in d:
+    return None
+  return d[key]