* Removed `type` and `info` fields from `Message` table and merged `privacy` field, previously into a separate table, into that table. In order to make the app work, when upgrading you should run the `migrate_0_4_to_0_5.py` script.
* Added flask-login dependency. Now, user logins can be persistent up to 365 days.
* Rewritten `enrich` filter, correcting a serious security flaw. The new filter uses a tokenizer and escapes all non-markup text. Plus, now the `+` of the mention is visible, but weakened; newlines are now visible in the message.