New
* Ability to pass queryset method from MessageIterator to underlying queryset. [artem.vasin]
* Message exclude support. [artem.vasin]
* Message pagination. [artem.vasin]
* Message filtering. [artem.vasin]
* Database message storage now provides `replies_count` to message. [artem.vasin]
* Database message storage now provides `replies` to message as `MessageIterator` [artem.vasin]
* Template tag {% update_last_checked %} for triggering update of last check date from template rendering. [artem.vasin]
* Added function `update_last` for manual change of last check date. [artem.vasin]
* Added properties to get sent messages and sent messages count at API, Backend, and Storage level. [artem.vasin]
* Added methods for changing message state at API, Backend, and Storage level. [artem.vasin]
Changes
* `mark_safe` wrapping moved fom `Message` model to `StoredMessage` class. [artem.vasin]
* Message and Inbox models in Database Backend now class-level constants MESSAGE_MODEL and INBOX model for easier subclassing of Database Backend. [artem.vasin]
* Database storage `_stored_to_message` method now converts `reply_to` from `models.Message` instance to `message_storage.base.StoredMessage` instance. [artem.vasin]
* No message-returning methods of database backend now updates last check date. Now you should manually trigger update via `update_last_checked` method. [artem.vasin]
Fix
* Counts in context processor now execute queries only when used in template. [artem.vasin]