[json] fix json serialization for recent simplejson implementation, and test encoding of entities
as with earlier simplejson implementation, iterencode internal stuff
is a generated function, we can't anymore rely on the _iterencode
overriding trick, so move on by stoping isinstance(Entity, dict).
This is a much heavier change than expected but it was expected
to be done at some point, so let's go that way.
<table class="attributeForm" style="width:100%;"
tal:attributes="id tab_id | nothing;
class tab_class | nothing;">
<tr tal:iter="widget lines">
<th class="labelCol" tal:content="structure python:widget.render_label(entity)">attrname</th>
<td tal:define="error python:widget.render_error(entity)" style="width:100%;"
tal:attributes="class python:error and 'error' or nothing">
<div tal:replace="structure error">error message if any</div>
<div tal:replace="structure python:widget.edit_render(entity)" >widget (input, textarea, etc.)</div>
<div tal:replace="structure python:widget.render_help(entity)">format help if any</div>
</td>
</tr>
</table>