Hotfix/voucher templates

Closes #266 (closed) and #267 (closed)

smash/web/forms/mail_template.py

+from django import forms
+from django.forms import ModelForm
+from web.models import MailTemplate
+
+import logging
+logger = logging.getLogger(__name__)
+
+class MailTemplateForm(ModelForm):
+    class Meta:
+        model = MailTemplate
+        fields = '__all__'
+
+    def __init__(self, *args, **kwargs):
+        super(MailTemplateForm, self).__init__(*args, **kwargs)
+
+        instance = getattr(self, 'instance', None)
+        
+        self.fields['Multilingual'] = forms.BooleanField(label='Multilingual', disabled=True, required=False,
+        	help_text='Only for voucher context. Check this option if the voucher template is multilingual.', 
+        	widget=forms.CheckboxInput(attrs={'class': 'hidden_form_field', 'id': 'multilingual_checkbox'}))
+
+    def clean(self):
+        cleaned_data = super(MailTemplateForm, self).clean()
+        return cleaned_data
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