wip: UI refactoring

* Webmail: better message display.
* Webmail: added optional Cc and Cci fields.

see #204

lib/templatetags/libextras.py

@@ -99,6 +99,12 @@ def render_field(field):
             field=field
             ))
 
+@register.simple_tag
+def render_and_hide_field(field):
+    return render_to_string("common/generic_field.html", dict(
+            field=field, hidden=True
+            ))
+
 @register.simple_tag
 def render_fields_group(form, pattern):
     from django.forms import forms