* Fix wrong README format.
* [FIX][base_import_match] Avoid UnicodeEncodeError.
When the model or field you chose was translated and had some non-ascii
character, you got an error like this: `UnicodeEncodeError: 'ascii' codec can't
encode character u'\xed' in position 15: ordinal not in range(128)`.
Now, using unicode strings, that won't happen again.
* Do not require a hidden field.
* Further unicode protection, add ondelete clause.