Add separate form for an additional survey after registration, advances #26.

Moved init code from registration ofmr, reusing it to add the same
fields to the registration form. Consider moving to a form set instead.

ticdesk_events/forms.py

@@ -134,6 +134,12 @@ class EventRegisterForm(forms.Form):
 
         self.fields['voucher_code'].validators.append(is_valid_voucher_for(project.cn))
 
+        EventAdditionSurveyForm.__init__(self, project, *args, **kwargs)
+
+class EventAdditionalSurveyForm(forms.Form):
+    def __init__(self, project, *args, **kwargs):
+        super(EventAdditionalSurveyForm, self).__init__(*args, **kwargs)
+
         for field in project.registration_fields:
             label, help_text, *choices = field.split('|')
             var = re.sub(r'\W|^(?=\d)', '_', label)