Django-mail-template

Added

- Add cc, bcc, reply_to fields to MailTemplate model.

- Add more translations.

Changed

- Now MailTemplate use EmailMultiAlternatives class for creating and sending
mails.

- MailTemplate body field is added to EmailMultiAlternatives instance as
body, and also attached as alternative as "text/html"

Added

- Add Description field to Configuration model.

- Add Description field to MailTemplate model.

- Add Title field to MailTemplate model.

- More elements for translation.

Changed

- Modify string representation of MailTemplate model. Each MailTemplate now is
represented by it's title.

Added

- New advanced section in documentation.

Changed

Added

- More elements for translation.

- Add verbose name (and tests) to models so they can be translated.

Changed

- replace_context_variable function follow [documentation example](https://docs.python.org/3/library/stdtypes.htmlstr.format_map)
using ``string.format_map`` instead of ``string.format`` and define Default
dict type for returning missing key value.

Added

- Migrations files.

- This change log file.

- Spanish locale translation.

Changed

- MailTemplate's body field change type from CharField to TextField.

- Documentation review.

First beta version.

All test and initial models.