[ADD] l10n_in_account_voucher : Add module for voucher report

- Task: https://www.odoo.com/web#id=7978&view_type=form&model=project.task&action=333&active_id=131
- Pad: https://pad.odoo.com/p/r.OUbis9qmMbFzF8J9
I have a crash when I try to test this email: 
```python
OpenERP Server Error
Traceback (most recent call last):
  File "/home/richard/odoo/openerp/http.py", line 500, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/home/richard/odoo/openerp/http.py", line 517, in dispatch
    result = self._call_function(**self.params)
  File "/home/richard/odoo/openerp/http.py", line 283, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/home/richard/odoo/openerp/service/model.py", line 113, in wrapper
    return f(dbname, *args, **kwargs)
  File "/home/richard/odoo/openerp/http.py", line 280, in checked_call
    return self.endpoint(*a, **kw)
  File "/home/richard/odoo/openerp/http.py", line 733, in __call__
    return self.method(*args, **kw)
  File "/home/richard/odoo/openerp/http.py", line 376, in response_wrap
    response = f(*args, **kw)
  File "/home/richard/odoo/addons/web/controllers/main.py", line 975, in call_kw
    return self._call_kw(model, method, args, kwargs)
  File "/home/richard/odoo/addons/web/controllers/main.py", line 967, in _call_kw
    return getattr(request.registry.get(model), method)(request.cr, request.uid, *args, **kwargs)
  File "/home/richard/odoo/openerp/api.py", line 237, in wrapper
    return old_api(self, *args, **kwargs)
  File "/home/richard/odoo/openerp/api.py", line 360, in old_api
    result = method(recs, *args, **kwargs)
  File "/home/richard/odoo/openerp/models.py", line 5729, in onchange
    record._onchange_eval(name, field_onchange[name], result)
  File "/home/richard/odoo/openerp/models.py", line 5663, in _onchange_eval
    method_res = getattr(self._model, method)(*args)
  File "/home/richard/odoo/openerp/api.py", line 237, in wrapper
    return old_api(self, *args, **kwargs)
  File "/home/richard/odoo/addons/email_template/wizard/email_template_preview.py", line 83, in on_change_res_id
    mail_values = email_template.generate_email(cr, uid, template_id, res_id, context=context)
  File "/home/richard/odoo/openerp/api.py", line 237, in wrapper
    return old_api(self, *args, **kwargs)
  File "/home/richard/odoo/addons/email_template/email_template.py", line 586, in generate_email
    return self.generate_email_batch(cr, uid, template_id, [res_id], context)[res_id]
  File "/home/richard/odoo/openerp/api.py", line 237, in wrapper
    return old_api(self, *args, **kwargs)
  File "/home/richard/odoo/addons/email_template/email_template.py", line 514, in generate_email_batch
    result, format = self.pool['report'].get_pdf(cr, uid, [res_id], report_service, context=ctx), 'pdf'
  File "/home/richard/odoo/openerp/api.py", line 237, in wrapper
    return old_api(self, *args, **kwargs)
  File "/home/richard/odoo/addons/report/models/report.py", line 181, in get_pdf
    html = self.get_html(cr, uid, ids, report_name, data=data, context=context)
  File "/home/richard/odoo/openerp/api.py", line 237, in wrapper
    return old_api(self, *args, **kwargs)
  File "/home/richard/odoo/addons/report/models/report.py", line 156, in get_html
    return particularreport_obj.render_html(cr, uid, ids, data=data, context=context)
  File "/home/richard/odoo/openerp/api.py", line 237, in wrapper
    return old_api(self, *args, **kwargs)
  File "/home/richard/odoo/openerp/api.py", line 332, in old_api
    result = method(recs, *args, **kwargs)
  File "/home/richard/odoo/addons/l10n_in_account_voucher/report/account_voucher_report.py", line 44, in render_html
    return report_obj.render('l10n_in_account_voucher.report_voucher', docargs)
  File "/home/richard/odoo/openerp/api.py", line 235, in wrapper
    return new_api(self, *args, **kwargs)
  File "/home/richard/odoo/openerp/api.py", line 552, in new_api
    result = method(self._model, cr, uid, self.ids, *args, **kwargs)
  File "/home/richard/odoo/addons/report/models/report.py", line 100, in render
    context.update(inherit_branding=True)  # Tell QWeb to brand the generated html
  File "/home/richard/odoo/openerp/tools/misc.py", line 1260, in update
    raise NotImplementedError("'update' not supported on frozendict")
NotImplementedError: 'update' not supported on frozendict
```