Fixed tag autocompletion

It yielded too many results in some cases.
Updated help
Fixed (un)banning users (missing column in DB)
Models: enhanced entities filtering
Fixed default safety
Fixed browsing settings
Paginator: A/D hotkeys disabled in endless mode
Reduced thumbnail size (PNG->JPG)
Closed #54 - added mass tag

- Moved tag forms to separate files
- Tag forms got tag autocompletion
CSS enhancements for focused elements