Create test_UnicodeDecodeError.eml

this message raise error on get_mail: 

Traceback:
File "/usr/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  114.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/usr/local/lib/python2.7/site-packages/django/views/generic/base.py" in view
  69.             return self.dispatch(request, *args, **kwargs)
File "/usr/local/lib/python2.7/site-packages/django/views/generic/base.py" in dispatch
  87.         return handler(request, *args, **kwargs)
File "/home/leha/django-site/proj/views.py" in get
  140.             messages = mailbox.get_new_mail()
File "/usr/local/lib/python2.7/site-packages/django_mailbox/models.py" in get_new_mail
  285.             msg = self.process_incoming_message(message)
File "/usr/local/lib/python2.7/site-packages/django_mailbox/models.py" in process_incoming_message
  183.         msg = self._process_message(message)
File "/usr/local/lib/python2.7/site-packages/django_mailbox/models.py" in _process_message
  266.         msg.save()
File "/usr/local/lib/python2.7/site-packages/django/db/models/base.py" in save
  545.                        force_update=force_update, update_fields=update_fields)
File "/usr/local/lib/python2.7/site-packages/django/db/models/base.py" in save_base
  573.             updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
File "/usr/local/lib/python2.7/site-packages/django/db/models/base.py" in _save_table
  654.             result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
File "/usr/local/lib/python2.7/site-packages/django/db/models/base.py" in _do_insert
  687.                                using=using, raw=raw)
File "/usr/local/lib/python2.7/site-packages/django/db/models/manager.py" in _insert
  232.         return insert_query(self.model, objs, fields, **kwargs)
File "/usr/local/lib/python2.7/site-packages/django/db/models/query.py" in insert_query
  1511.     return query.get_compiler(using=using).execute_sql(return_id)
File "/usr/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py" in execute_sql
  898.             cursor.execute(sql, params)
File "/usr/local/lib/python2.7/site-packages/django/db/backends/util.py" in execute
  73.             sql = self.db.ops.last_executed_query(self.cursor, sql, params)
File "/usr/local/lib/python2.7/site-packages/django/db/backends/postgresql_psycopg2/operations.py" in last_executed_query
  214.             return cursor.query.decode('utf-8')
File "/usr/local/lib/python2.7/encodings/utf_8.py" in decode
  16.     return codecs.utf_8_decode(input, errors, True)

Exception Type: UnicodeDecodeError at /proj/new_mail/
Exception Value: 'utf8' codec can't decode byte 0xd3 in position 187: invalid continuation byte
Always decode headers into unicode objects before assigning to model; fixes #12.
Bumping version number to 3.1.