Small release compared to previous one, but it does one amazing thing. Now all messages from user or operators will be checked using same query. Last message ID algorithm for user was implemented. I think it's one of the last performance related part. Futher updates will include more features than refactoring. We now have really nice live support engine.

Resume:

• Removed status column from messages table, not needed anymore.
• Same check messages algorithm for admin and user.
• Only one index is needed now for messages table. Improves write operations and eliminates update in user sync call.

execute doc/update_db/update_17.sql and follow standard upgrade instructions.